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6.6L Duramax Diesel Engine Supplement

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20_MUL_6.6L_Duramax_Diesel_Engline_Supplement__COV_en_US_84458631A_2019APR11.ai 1 3/21/2019 11:06:49 AM20_MUL_6.6L_Duramax_Diesel_Engline_Supplement__COV_en_US_84458631A_2019APR11.ai 1 3/21/2019 11:06:49 AM

Chevrolet/GMC 6.6L Duramax Diesel Engine Supplement (GMNA-Localizing-U.S./Canada-13337828) - 2020 - CRC - 4/17/19

Contents Introduction . . . . . . . . . . . . . . . . . . . . . . 2

Instruments and Controls . . . . . . . . 5

Driving and Operating . . . . . . . . . . 15

Vehicle Care . . . . . . . . . . . . . . . . . . . . 60

Service and Maintenance . . . . . . . 79

Technical Data . . . . . . . . . . . . . . . . . 88

Index . . . . . . . . . . . . . . . . . . . . . 92


2 Introduction

IntroductionThe names, logos, emblems,slogans, vehicle model names, andvehicle body designs appearing inthis manual including, but not limitedto, GM, the GM logo, CHEVROLET,GMC, the CHEVROLET and GMCTruck Emblems, SILVERADO,SIERRA, DENALI, and Duramax aretrademarks and/or service marks ofGeneral Motors LLC, itssubsidiaries, affiliates, or licensors.

For vehicles first sold in Canada,substitute the name “GeneralMotors of Canada Company” forGMC and Chevrolet Motor Divisionwherever it appears in this manual.

This manual describes features thatmay or may not be on the vehiclebecause of optional equipment thatwas not purchased on the vehicle,

model variants, countryspecifications, features/applicationsthat may not be available in yourregion, or changes subsequent tothe printing of this owner’s manual.

Refer to the purchasedocumentation relating to yourspecific vehicle to confirm thefeatures.

This manual contains informationthat pertains to the operation of yourdiesel engine. It also contains yourDiesel Maintenance Schedule. Thesections in this manual correspondto the sections in your owner’smanual. This manual, along withyour owner’s manual, will assist youin the proper use and maintenanceof your vehicle.

Keep this manual in the vehicle forquick reference.

Canadian Vehicle OwnersA French language manual can beobtained from your dealer, atwww.helminc.com, or from:

Propriétaires Canadiens

On peut obtenir un exemplaire dece guide en français auprès duconcessionnaire ou à l'adressesuivante:

Helm, IncorporatedAttention: Customer Service47911 Halyard DrivePlymouth, MI 48170USA

Using this SupplementThis supplement containsinformation specific to the uniquecomponents of the vehicle. It doesnot explain everything you need toknow about the vehicle. Read thissupplement along with the owner’smanual to learn about the vehicle'sfeatures and controls.

Litho in U.S.A.Part No. 84458631 A First Printing ©2019 General Motors LLC. All Rights Reserved.


Introduction 3

Index

A good place to look for what youneed is the Index in the back of thissupplement. It is an alphabetical listof what is in the supplement, andthe page number where you willfind it.


4 Introduction

2 NOTES


Instruments and Controls 5

Instruments andControls

Warning Lights, Gauges, andIndicatorsInstrument Cluster . . . . . . . . . . . . . . 6Malfunction Indicator Lamp(Check Engine Light) . . . . . . . . . 10

Wait-to-Start Light . . . . . . . . . . . . . . 11Diesel Exhaust Fluid (DEF)Warning Light . . . . . . . . . . . . . . . . 11

Power Take-Off Light . . . . . . . . . . 12

Information DisplaysDriver InformationCenter (DIC) . . . . . . . . . . . . . . . . . 12

Vehicle PersonalizationVehicle Personalization . . . . . . . . 13


6 Instruments and Controls

Warning Lights, Gauges, and Indicators

Instrument Cluster

Base Level Chevrolet English Cluster, Metric Similar



Base Level GMC English Cluster, Metric Similar



Uplevel GMC English Cluster, Metric Similar



Uplevel Chevrolet English Cluster, Metric Similar



Malfunction IndicatorLamp (Check EngineLight)This light is part of the vehicle’semission control on-boarddiagnostic system. If this light is onwhile the engine is running, amalfunction has been detected andthe vehicle may require service. Thelight should come on to show that itis working when the ignition is onwith the engine not running. See“Ignition Positions” in the owner’smanual.

This light may also come on whenthe system has detected a problemwith the Diesel Exhaust Fluid (DEF)management system. See DieselExhaust Fluid 0 25.

Malfunctions are often indicated bythe system before any problem isnoticeable. Being aware of the lightand seeking service promptly whenit comes on may prevent damage.

Caution

If the vehicle is driven continuallywith this light on, the emissioncontrol system may not work aswell, the fuel economy may belower, and the vehicle may notrun smoothly. This could lead tocostly repairs that might not becovered by the vehicle warranty.

Caution

Modifications to the engine,transmission, exhaust, intake,or fuel system, or the use ofreplacement tires that do notmeet the original tirespecifications, can cause this lightto come on. This could lead to

(Continued)

Caution (Continued)

costly repairs not covered by thevehicle warranty. This could alsoaffect the vehicle’s ability to passan Emissions Inspection/Maintenance test. SeeAccessories and Modifications0 60.

When the light is on, a malfunctionhas been detected. Diagnosis andservice may be required.

Poor fuel quality can causeinefficient engine operation and poordriveability, which may go awayonce the engine is warmed up.If this occurs, change the fuel brand.It may require at least one full tankof the proper fuel to turn the light off.See Fuel for Diesel Engines 0 30.

If the light remains on, see yourdealer.



Emissions Inspection andMaintenance Programs

If the vehicle requires an EmissionsInspection/Maintenance test, thetest equipment will likely connect tothe vehicle's Data LinkConnector (DLC).

The DLC is under the instrumentpanel to the left of the steeringwheel. Connecting devices that arenot used to perform an EmissionsInspection/Maintenance test or toservice the vehicle may affectvehicle operation. See “Add-OnElectrical Equipment” in the owner’smanual. See your dealer ifassistance is needed.

The vehicle may not passinspection if:

. The light is on when the engineis running.

. The light does not come onwhen the ignition is on with theengine not running.

. Critical emission control systemshave not been completelydiagnosed. If this happens, thevehicle would not be ready forinspection and might requireseveral days of routine drivingbefore the system is ready forinspection. This can happen ifthe 12-volt battery has recentlybeen replaced or run down, or ifthe vehicle has recently beenserviced.

See your dealer if the vehicle willnot pass or cannot be made readyfor the test.

Wait-to-Start Light

This light comes on briefly whilestarting the engine, as a check toshow the light is working.

If the wait-to-start light comes on,the glow plug system is requiredand operating. Wait until the lightturns off before starting the engine.This light may not come on in warmtemperatures.

The fast warm-up glow plug systemmakes the wait-to-start light stay onfor a shorter amount of time thanmost diesel engines.

See Starting the Diesel Engine 0 15.

Diesel Exhaust Fluid(DEF) Warning Light

This light, a Driver InformationCenter (DIC) message, and a chimecome on when there is an issue withthe Diesel Exhaust Fluid.



If the DEF level has not beencorrected, the light will continue toflash when the vehicle is started.The vehicle's speed may also belimited.

Also see Diesel Exhaust Fluid 0 25.

Power Take-Off Light

Chassis Cab

The vehicle may have a PowerTake-Off (PTO) light. Under normaloperating conditions, the PTO lightwill remain on throughout the PTOoperating cycle. If all conditionsrequired to engage PTO have notbeen met when enabling PTO, thePTO light will turn on, then turn offafter one second. See PowerTake-Off (PTO) 0 41.

Information Displays

Driver InformationCenter (DIC)The DIC is in the instrument cluster.The DIC comes on when the ignitionis on.

A Duramax diesel vehicle may havethe following additional DIC menuitems:

DEF : Displays the Diesel ExhaustFluid (DEF) level as a bar graphwith individual segments thatilluminate from Empty (E) to Full (F).When LOW appears on the displayand the segments turn red, addDEF as soon as possible. For aguide on how much DEF to add,see Diesel Exhaust Fluid 0 25.

Fuel Filter Life Remaining : Thisdisplay shows an estimate of thefuel filter's remaining useful life.If 90% Fuel Filter Life Remaining isdisplayed, it means 90% of thecurrent fuel filter life remains. Thefuel filter life system will alert when

to change the fuel filter on aschedule consistent with yourdriving conditions.

When the remaining fuel filter life islow, the CHANGE FUEL FILTERmessage will appear on the display.Change the fuel filter as soon aspossible.

Fuel Filter Life Reset : Reset theFuel Filter Life Remaining displayafter each fuel filter change. It willnot reset itself. Also, be careful notto reset the display at any time otherthan when the fuel filter has justbeen changed because it cannot bereset accurately until the next fuelfilter change. The fuel filter life willchange to 100% when the systemhas been reset. To reset the system,press and hold the thumbwheel fortwo seconds while Fuel Filter LifeRemaining is displayed on the DIC.



Engine Air Filter Life : Displays anestimate of the engine air filter’sremaining useful life and the state ofthe system. Engine Air Filter Life95% means 95% of the current airfilter life remains. Messages willdisplay based on the engine air filterlife and the state of the system.When the REPLACE AT NEXT OILCHANGE message displays, theengine air filter should be replacedat the time of the next oil change.When the REPLACE SOONmessage displays, the engine airfilter should be replaced at theearliest convenience. The Air FilterLife display must be reset after theengine air filter replacement. Toreset, see Engine Air Filter LifeSystem 0 66.

VehiclePersonalizationUse the audio system controls toaccess the personalization menusfor customizing vehicle features.

The following features may beavailable on some vehicles with adiesel engine. See “VehiclePersonalization” in the owner’smanual for additional vehiclepersonalizations.

If equipped, these features may beselected using the infotainmentdisplay.

To access the vehiclepersonalization menu:

1. Touch the Settings icon on theHome Page of the infotainmentdisplay.

2. Touch Vehicle to display a listof available options.

3. Touch to select the desiredfeature setting.

4. Touch9 or R to turn a featureoff or on.

5. Touch z to go to the top levelof the Settings menu.

Climate and Air Quality

Select and the following maydisplay:

. Rapid Heat-Elevated Idle

Rapid Heat-Elevated Idle

This allows the feature to be turnedon and off. See “Elevated Idle” inStarting the Diesel Engine 0 15.

Select Off or On.

Power Take-Off (PTO) (IfEquipped)

There may be additional featuresthat can be customized for the PTO.See Power Take-Off (PTO) 0 41.See your dealer to enable thesefeatures.

Select and the following maydisplay:

. Standby Speed

. Set 1 Speed

. Set 2 Speed


14 Instruments and Controls. Tap Step Speed

. Shutdown Time

STANDBY SPEED

This feature allows for modifying thePTO Standby Speed.

Select the desired setting.

SET 1 SPEED

This feature is available if thevehicle is configured for stationarypreset PTO, and allows theselection of the PTO set 1 speed.

Select the desired PTO Standby Set1 setting.

SET 2 SPEED

This feature is available if thevehicle is configured for stationarypreset PTO, and allows theselection of the PTO set 2 speed.

Select the desired PTO Standby Set2 setting.

TAP STEP SPEED

This feature is available if thevehicle is configured for stationaryvariable or mobile PTO, and allowsthe selection of the PTO tap stepspeed.

Select the desired PTO TapStep Speed setting.

SHUTDOWN TIME

This feature is available if thevehicle is configured for stationarypreset or stationary variable PTO,and allows the selection of the PTOshutdown time.

Select the desired PTO ShutdownTime setting.


Driving and Operating 15

Driving andOperating

Starting and OperatingStarting the Diesel Engine . . . . . 15Winter Cover . . . . . . . . . . . . . . . . . . . 18Engine Heater . . . . . . . . . . . . . . . . . 21Parking over ThingsThat Burn . . . . . . . . . . . . . . . . . . . . 22

Diesel Particulate FilterDiesel Particulate Filter . . . . . . . . 22

Diesel Exhaust FluidDiesel Exhaust Fluid . . . . . . . . . . . 25

BrakesExhaust Brake . . . . . . . . . . . . . . . . . 29

FuelTop Tier Fuel . . . . . . . . . . . . . . . . . . 30Fuel Additives . . . . . . . . . . . . . . . . . 30Fuel for Diesel Engines . . . . . . . . 30Biodiesel . . . . . . . . . . . . . . . . . . . . . . . 31Cold Weather Operation . . . . . . . 32Water in Fuel . . . . . . . . . . . . . . . . . . 33Running Out of Fuel . . . . . . . . . . . 36Fuel Filter Replacement . . . . . . . 36Filling the Tank . . . . . . . . . . . . . . . . 37

Filling a Portable FuelContainer . . . . . . . . . . . . . . . . . . . . . 39

Trailer TowingTrailer Towing . . . . . . . . . . . . . . . . . . 39

Conversions and Add-OnsPower Take-Off (PTO) . . . . . . . . . 41

Starting andOperating

Starting the DieselEngineThe diesel engine starts differentlythan a gasoline engine.

Caution

If the steering wheel is turneduntil it reaches the end of itstravel, and is held in that positionwhile starting the vehicle, damagemay occur to the hydraulic powersteering system and there may beloss of power steering assist.

Move the shift lever to P (Park) orN (Neutral). To restart the enginewhen the vehicle is already moving,use N (Neutral) only.


16 Driving and Operating

Caution

Do not try to shift to P (Park) if thevehicle is moving. If you do, youcould damage the transmission.Shift to P (Park) only when thevehicle is stopped.

Starting the Engine

1. Turn the ignition key toON/RUN.

Observe the wait-to-start light.See Wait-to-Start Light 0 11.This light may not come on ifthe engine is warm.

2. If the wait-to-start light is on,wait until this light goes off.Turn the ignition key to START,then release the ignition key.The engine will continue tocrank until the engine starts.

The engine has a fast warm-upglow plug system. Thewait-to-start light will illuminatefor a much shorter time than

most diesel engines, due to therapid heating of the glow plugsystem.

Caution

If the wait-to-start light stays onafter starting the vehicle, thevehicle may not run properly.Have the vehicle servicedright away.

3. If the engine does not startafter 15 seconds of cranking,turn the ignition off. Waitone minute for the crankingmotor to cool, then try thesame steps again.

If you are trying to start the engineafter you have run out of fuel, followthe steps in Running Out of Fuel0 36.

When the engine is cold, let it runfor a few minutes before driving.This lets oil pressure build up. Theengine will sound louder when itis cold.

For turbo protection, engine powerat speeds above idle may be limitedif the engine is cold. This protectioncan last up to 40 seconds atextreme cold coolant and ambienttemperatures.

Cold Weather Starting

Use the recommended engine oilwhen the outside temperaturedrops below freezing. See EngineOil 0 63. When the outsidetemperature drops below –18 °C(0 °F), use of the engine coolantheater is recommended.

If you experience longer crankingtimes, notice an unusual amount ofexhaust smoke, or are at higherelevations (over 2 135 m or 7,000 ft),you may use the engine coolantheater. See Engine Heater 0 21.

See Fuel for Diesel Engines 0 30 forinformation on what fuel to use incold weather.

If the Diesel Engine Will NotStart

If the vehicle runs out of fuel, seeRunning Out of Fuel 0 36.



If the vehicle is not out of fuel, andthe engine will not start:

Turn the ignition key to ON/RUN.After the wait-to-start light goes off,turn the ignition key to START.

If the light does not go off, wait afew seconds, then try starting theengine again. See your dealer assoon as you can for a startingsystem check.

If the light comes on and then goesoff and you know the batteries arecharged, but the engine still will notstart, the vehicle needs service.

If the light does not come on whenthe engine is cold, the vehicleneeds service.

If the batteries do not have enoughcharge to start the engine, see“Battery” in the owner’s manual.

Check that the correct engine oilhas been used and changed atappropriate intervals. If the wrong oilis used, the engine may be harderto start.

Be sure you are using the properfuel for existing weather conditions.See Fuel for Diesel Engines 0 30.

If the engine starts, runs a shorttime, then stops, the vehicle needsservice.

{ Warning

Do not use gasoline or startingaids, such as ether, in the airintake. They could damage theengine, which may not becovered by the vehicle warranty.They could also cause a fire,which could cause seriouspersonal injury.

Engine Idle Variations

Under certain conditions the engineidle speed can vary or be elevated.Change in idle speed is normal anddoes not indicate a problem. Normalconditions that can raise idle speedare low voltage, DPF regeneration,air conditioning compressor loads,

and engine warmup. These speedscan range from approximately 600to 1000 rpm.

Elevated Idle

The engine has a cold temperaturehigh idle feature which elevates theengine idle speed from base idle to1050 to 1100 rpm when outsidetemperatures are below 0 °C (32 °F),and the engine coolant temperatureis below 65 °C (150 °F). This featureenhances heater performance byraising the engine coolanttemperature faster.

To turn this feature on or off, seeVehicle Personalization 0 13.

When the engine is started, it willslowly ramp up to the high idlespeed after a delay of a fewseconds up to approximatelytwo minutes. For this method towork properly there must be nothrottle or brake pedal faults.

The engine idle speed will return tonormal once the following conditionsare met:


18 Driving and Operating. Engine coolant temperature

reaches 65 °C (150 °F).

. Air intake temperature reaches0 °C (32 °F).

The high idle speed will betemporarily interrupted and theengine speed will return to normal ifany of the following conditionsoccur:

. The brake pedal is applied.

. The accelerator pedal ispressed.

. The transmission is shifted outof P (Park) or N (Neutral).

. Vehicle speed is detected.

Once these inputs are removed, theengine idle speed will slowly rampback up to high idle after the normaldelay, if the conditions for enginecoolant temperature and air intaketemperature are still met.

Fast Idle Control

If equipped, this system can beused to increase the engine idlespeed.

Fast Idle control will be enabledwhen the following conditionsare met:

. The parking brake is set.

. The transmission is in P (Park)or N (Neutral).

. The vehicle speed is about0 km/h (0 mph).

. The cruise control Set switch ispressed and released for PresetFast Idle Speed (1200 rpm).

Fast Idle control will be disabledwhen one or more of the followingconditions occur:

. The cruise control Set switch ispressed and released. See“Cruise Control” in the owner’smanual.

. The cruise control Cancel switchis pressed.

. The brake pedal is pressed.

. The transmission is shifted outof P (Park) or N (Neutral).

. The parking brake is released.

. The vehicle speed is not0 km/h (0 mph).

Winter CoverIf equipped, the winter cover can beused to enhance heaterperformance in extremely coldconditions below −4 °C (25 °F). Thewinter cover installs over the grilleand restricts airflow to the enginecompartment.

For vehicles that did not come witha winter cover, a GM winter covercan be purchased. See your dealerfor additional information.

When the winter cover is in use, theheater, ventilation, and airconditioning AUTO mode may notfunction properly. Use the manualsettings for comfort.

Usage Guidelines

The winter cover should only beused while operating the vehicle inextremely cold temperatures or inheavy snow for extended periods. Inthese temperatures, the vehicledoes not need a large amount of air



to properly cool the engine. Whenmore airflow is required to cool thevehicle, the winter cover should notbe used. The following usageguidelines will allow adequateairflow for proper radiator and aircooler performance:

. Do not use the winter cover iftowing a trailer in conditionsabove 10 °C (50 °F). The vehiclemay overheat if the radiator iscovered while towing.

. Do not use the winter cover if asnow plow is mounted on thetruck.

. Do not cover the opening in thefront bumper.

. Do not modify the cover. Thewinter cover does not coversome sections of the front of thevehicle to provide enoughairflow.

. When the winter cover is used,the outside air temperaturedisplay may not functionproperly.

. Keep the underside of the wintercover as clean as possible.Remove monthly or asnecessary and clean away dustand debris.

. Use only a mild soap to clean.Do not use harsh soap, strongdetergents, or vinyl protectant/sealant type products as theymay damage the special finish.Allow the winter cover to drycompletely before reinstalling.

Installation Instructions

When first trying to fit the cover, itmay appear to be undersized butwill stretch during installation to

ensure a tight fit. The initialinstallation of the cover is bestperformed when the winter coveris warm.

Installation (Chevrolet Pickup)

1. The white label must be at thetop and back of the cover.



2. Starting in the middle, attachfastening points as illustrated.

3. To remove, reverse the stepslisted previously.

Installation (GMC Pickup)

1. The white label must be at thetop and back of the cover.



2. Starting in the middle, attachfastening points as illustrated.

3. To remove, reverse the stepslisted previously.

Engine Heater

{ Warning

Do not plug in the engine blockheater while the vehicle is parkedin a garage or under a carport.Property damage or personalinjury may result. Always park thevehicle in a clear open area awayfrom buildings or structures.

If equipped, the engine heater canprovide easier starting in coldweather conditions at or below−18 °C (0 °F).

For engine heater operation, see“Engine Heater” in the owner’smanual.



Parking over ThingsThat Burn

{ Warning

Things that can burn could touchhot exhaust parts under thevehicle and ignite. Do not parkover papers, leaves, dry grass,or other things that can burn.

Diesel ParticulateFilterThe exhaust system has a DieselParticulate Filter (DPF) to reducevehicle emissions. On someexhaust systems with a DPF, theexhaust cooler mixes air with theexhaust to lower the temperaturebefore it leaves the tailpipe.

The DPF, the tailpipe, and otherexhaust system components mustnot be altered. Inspect regularly andclean any mud or dirt from theexhaust cooler, especially where theexhaust cooler connects to thetailpipe and the openings wherefresh air enters the cooler.

The DPF will clean itself as part ofnormal operation. Several factorsincluding fuel consumed, hours ofengine operation, and miles drivenare monitored by the Engine ControlModule (ECM). The self-cleaningoccurs approximately once per tankof fuel.

Vehicles with the DPF have specificfuel and engine oil requirements.See Fuel for Diesel Engines 0 30andEngine Oil 0 63.

Caution

Damage can occur to the DPFcomponents if the required UltraLow Sulfur Diesel (15 ppm sulfurmaximum) fuel and either CJ-4 orCK-4 engine oil are not used.This damage would not becovered by the vehicle warranty.

Under certain conditions, such asidling or very short trips, theself-cleaning process has lessefficiency and cannot be completed.

To resolve this, continue drivingsafely at a steady speed as close tothe posted speed limit as possible,preferably without stopping, until themessage turns off. This can take upto 30 minutes.



{ Warning

During DPF self-cleaning orduring extended idling in P (Park),the exhaust system and exhaustgases are very hot. Things thatburn could touch hot exhaustparts under the vehicle and ignite.You or others could be burned.Do not park, or idle for anextended period of time, near orover papers, leaves, dry grass,or other things that can burn.Keep the exhaust area clear ofmaterial that could ignite or burn.See Parking over Things ThatBurn 0 22.

Caution

Avoid extended idling becausethe DPF system is not capable ofself-cleaning at idle. Duringextended idling, monitor theinstrument cluster lights and DIC

(Continued)

Caution (Continued)

for messages and takeappropriate action. Continuedidling with the warning light/message on could cause damageto the DPF requiring repair andpossible replacement that mightnot be covered by the vehiclewarranty.

During self-cleaning there will be achange in the exhaust sound andengine idle speed. Along with this, aburning smell and reduction in fueleconomy may be noticed. This isnormal.

If the vehicle is idled or driven onvery short trips with the DPFwarning message on and theexhaust filter is not cleaned asrequired, the malfunction indicatorlamp and a DIC message willdisplay. See your dealer. Also seeMalfunction Indicator Lamp (CheckEngine Light) 0 10.

If equipped with PowerTake-Off (PTO), monitor theinstrument cluster for lights relatedto the DPF.

See Accessories and Modifications0 60 if you are adding accessoriesor modifying the vehicle.

Manual Regeneration of DieselParticulate Filter

This feature is only available onFleet and Commercial vehicles.

To verify that the vehicle has thisfeature, refer to the Vehicle ServiceParts Identification label (SPID) forRPO code FPF or seewww.gmupfitter.com to contact theGM Upfitter Integration Group.

If equipped, this feature allows formanual cleaning/regeneration of theDPF when it is unable to cleanitself. It may be necessary toperform manual regeneration ifdriving conditions — such asextended slow speed, stop-and-gotraffic, extended idling, short drivecycles, or stationary PTO operation— prevent DPF self-cleaning.



Manual regeneration can only beused when the DPF has become atleast 90% full. At 100% full, it willattempt to automatically self-clean ifproper driving conditions are met.The DPF will clean itself if thevehicle can be driven for about30 minutes.

A DIC message displays whenmanual regeneration is possible.

Scroll through the DIC pages to findthe Exhaust Cleaning menu.Depending on whether the vehiclehas a base or uplevel cluster, it maybe under the Settings menu.

If the vehicle cannot be stoppedwhen the DIC message firstindicates cleaning is available,automatic self-cleaning may havebegun. If conditions cannot be metfor self-cleaning to complete, andmanual regeneration is selected, itmay take up to four minutes for thesystem to switch to manualregeneration. When the switchoccurs, a DIC message prompts tostart the cleaning process.

{ Warning

Do not leave the vehicle duringthe regeneration.

Make sure that there are noflammable materials near themuffler, DPF, and exhaust pipewhich may result in a fire.

The temperature of exhaustgases is high enough to burn you.You and others could be seriouslyinjured.

Before starting manualregeneration, make sure all of thefollowing safety conditions are met:

. The vehicle is parked on levelground, away from anyflammable materials.

. The vehicle is parked outdoors,away from any walls orbuildings.

. The vehicle is at least 3 m (10 ft)from any obstructions ormaterials that may combustor melt.

. The shift lever is in P (Park).

. The fuel tank is at leastone-eighth full.

. All fluids are at the proper level.

. No diagnostic trouble codeshave been set, and themalfunction indicator lamp isnot on.

. The engine coolant temperatureis above 71 °C (160 °F).

After making sure all safetyconditions have been met, press thetrip odometer reset stem orthumbwheel on the steering wheelfor at least one second to selectStart on the infotainment display.

Follow the instructions in the DICmessages. Touch ACCEPT toacknowledge that all of these safetyconditions have been met and toactivate regeneration.

If the infotainment display returns tothe previous screen, then one ormore of the necessary safetyconditions has not been met. If youcannot determine which condition



has not been met, seewww.gmupfitter.com to contact theGM Upfitter Integration Group.

Continue to follow the instructions inthe DIC messages. Hold theexhaust brake switch on the centerstack below the climate controls formore than three seconds, and thenrelease it, to begin the regenerationprocess.

If the EXHAUST BRAKE ONmessage displays, then the switchwas released too soon. Press itagain to turn off the exhaust brake,then try again when the DICmessage prompts.

When manual regeneration begins,the engine speed increases, theengine cooling fan sound increases,and a DIC message indicates thatcleaning is in progress.

A DIC message will display whencleaning is complete. Cleaningcould take up to 30 minutes. Uponcompletion, the engine will return tonormal idle, but exhaustcomponents will remain hot forseveral minutes. Do not move thevehicle until the exhaust has hadtime to cool. Manual regenerationcan be canceled at any time bypressing the brake pedal or byturning the engine off. Unusualnoises may be heard if regenerationis interrupted.

Diesel Exhaust Fluid

{ Warning

Avoid getting Diesel ExhaustFluid (DEF) on your skin or inyour eyes as it could causeirritation. For more safety,handling, and storage information,see the Diesel Exhaust Fluidcontainer label.

Caution

Use only DEF that is GMapproved, or fluid containing theAPI certified or ISO 22241 label.The use of other fluids coulddamage the system, requiringcostly repairs that will not becovered by the vehicle warranty.



Caution

Do not mix with or add DEF to thediesel fuel. This could lead tocostly repairs not covered by thevehicle warranty.

Diesel Exhaust Fluid (DEF) is usedwith diesel engines to reduce theamount of regulated emissionsproduced. Products such as AdBlueare types of DEF. The fluid level inthe DEF tank must be maintainedfor the vehicle to run properly. DEFis not a fuel additive. DEF freezeswhen exposed to temperaturesbelow −11 °C (12 °F). For DEF tankcapacity see Capacities andSpecifications 0 89.

It is normal to hear the DEF systempurge fluid back into the tank afterthe vehicle is shut off.

Locating Diesel Exhaust Fluid

DEF can be purchased at yourauthorized dealers. Additionally,some diesel truck fueling stations orretailers may have DEF forpurchase. For vehicles with anactive OnStar or connected servicesplan, OnStar can help to locate aDEF retailer. See “CustomerAssistance Offices” in the owner’smanual for phone numbers to assistin contacting a dealer. SeeRecommended Fluids andLubricants 0 85.

Filling the DEF Tank

The blue DEF cap is behind thefuel/DEF door. Do not remove thefuel and DEF caps at the sametime. Fill diesel fuel and DEFindependently. Turn the DEF capcounterclockwise to remove.

In cold conditions DEF can freeze inthe DEF fill pipe opening. If thisprevents the filling of the DEF tank,place the vehicle in a warm garageovernight.



Fill the DEF tank on level groundand with the vehicle off. Whenadding DEF, it is recommended tofully fill the DEF tank. For DEF tank

capacity see Capacities andSpecifications 0 89. When addingDEF to an empty or very low tank,

always add at least 7.5 L (2 gal) offluid to release the vehicle fromspeed limitation.

If DEF is added under freezingconditions it may require less fluid tofill the DEF tank.

When fluid reaches the top of theDEF fill pipe, stop filling. Do not topoff the DEF tank. If using a bottle orjug to refill DEF, follow theinstructions on the container labeland use a dedicated fill aid.

Caution

Do not overfill the DEF tank anddo not allow DEF to contact thefinished surfaces of the vehicle,as it could damage the vehiclefinish. If DEF is spilled duringfilling, wipe any affected surfacewith a damp cloth.

When replacing the DEF cap, turn itclockwise until it clicks. Make surethe cap is fully installed.

Push the fuel/DEF door closed.



DEF Low

As the DEF level drops, warningswill automatically be displayed in theDriver Information Center (DIC).Select Vehicle Information in theDIC to view DEF level status. SeeDriver Information Center (DIC)0 12.

Refill the DEF tank at the firstopportunity after a low warningindication to avoid vehicle speedlimitations.

It may take some time for thevehicle to detect that DEF has beenadded. If there was a vehicle speedlimitation, it will be removedgradually and it may take severalkilometers/miles for the DICmessage to update.

If DEF is added under freezingconditions, additional time may berequired to remove speedlimitations.

The DEF range DIC message firstdisplays at approximately 1 600 km(1,000 mi). This message appearsagain at approximately 500 km

(300 mi) of remaining range beforethe exhaust fluid tank becomesempty.

As the fluid level nears empty, thesemessages appear every time thevehicle is started.

If the DEF low warnings are ignoredand the DEF tank becomes empty,the DIC will display messages thatdescribe the action needed anddistance until vehicle speed islimited. For the DEF warning lightsymbol, see Diesel Exhaust Fluid(DEF) Warning Light 0 11.

DEF Quality Poor

Use only DEF that is GM approved,or fluid containing the API certifiedor ISO 22241 label.

DEF has an expiration date. If thesystem detects poor quality,or contaminated or diluted DEF, aDIC message will display along withdistance until vehicle speed islimited.

The speed limitation will occur in aseries of steps with the final speedlimitation being 8 km/h (5 mph)along with a flashing warning lightand chimes.

Adding fresh DEF to the systemmay resolve the problem afterseveral kilometers/miles of driving,depending on several factors. If theDIC message persists, see yourdealer or additional DIC messagesmay display.

Service DEF System

If a problem occurs with the DEFsystem, a DIC message displaysalong with distance until vehiclespeed is limited.

The speed limitation will occur in aseries of steps with the final speedlimitation being 8 km/h (5 mph)along with a flashing warning lightand chimes.

In some cases, this message willclear itself, indicating that the DEFsystem was able to correct thecondition. If the DIC message



persists, see your dealer oradditional DIC messages maydisplay.

Service Emission System

If a problem occurs with the vehicleemission system, a DIC messagedisplays along with distance untilvehicle speed is limited. The speedlimitation will occur in a series ofsteps with the final speed limitationof 88 km/h (55 mph) and chimes. Insome cases, this message will clearitself, indicating that the emissionsystem was able to correct thecondition. If the DIC messagepersists, see your dealer oradditional DIC messages maydisplay.

Brakes

Exhaust BrakeThe exhaust brake can be used toenhance the vehicle brake systemand reduce brake lining wear.

Downshifts may be automaticallyselected to increase engine speed,which increases the effectiveness ofthe exhaust brake. The number ofdownshifts selected is determinedby the length of time the brakes areapplied and the rate the vehicle isslowing. The system delivers thecorrect amount of braking to assistin vehicle control. The heavier thevehicle load, the more active theengine exhaust brake will be. Use ofthe exhaust brake will help maintainvehicle speed when used withcruise control. See “Cruise Control”in the owner’s manual.

Automatic downshifts will not occurif the vehicle is in Range SelectionMode. See “Manual Mode” in theowner’s manual.

The exhaust brake only activateswhen the transmission torqueconverter is locked. This can varybased on vehicle speed, gear,and load.

To activate the system, pressEXHAUST BRAKE q on the centerstack.

A light in the switch will come onwhen the exhaust brake isactivated. The switch must bepressed at each vehicle start for thesystem to be active.

The Driver Information Center (DIC)displays the message EXHAUSTBRAKE ON for approximatelythree seconds, then clears.

To turn the brake off, press theexhaust brake switch a second time.The DIC displays the messageEXHAUST BRAKE OFF forapproximately three seconds, thenclears.

The exhaust brake will be moreactive when in Tow/Haul Mode.



Fuel

Top Tier FuelGM recommends the use of TOPTIER Diesel Fuel to keep the engineclean, reduce engine deposits, andmaintain optimal vehicleperformance. Look for the TOPTIER Logo or seewww.toptiergas.com for a list of TOPTIER Diesel Fuel marketers andapplicable countries.

Fuel AdditivesTOP TIER Detergent Diesel ishighly recommended for use withyour vehicle. If your area does nothave TOP TIER Detergent Diesel,GM recommends the use ofACDelco Diesel Fuel Conditioner.This will help maintain optimalengine performance. GM does notrecommend other aftermarket dieseladditives.

If low-quality diesel is used forrefueling, GM recommends addingACDelco Fuel System TreatmentPlus-Diesel to help clean enginedeposits. This is available only atyour GM dealer.

Fuel for Diesel EnginesThe selection of a high-quality fuelis important for maintaining optimumvehicle performance. Diesel fuelshould meet or exceed the minimumrequirements in the most currentversions of the local fuel standards.

Do not use fuel with more than 15ppm sulfur.

Do not use a diesel blend containingmore than 20% biodiesel by volume.

Caution

Use of fuel that does not complywith the required technicalstandards can lead to enginepower loss, increased wear,or engine damage and may voidyour warranty.

Some improper fuels are:

. Diesel fuel with the additionof gasoline.

. Diesel fuel mixed withengine oil or automatictransmission fluid.

. Triglyceride fuels, such asraw vegetable oil or animalfat, in any form, includingwith blends of diesel orbiodiesel.

. Marine diesel fuel andfuel oils.

(Continued)



Caution (Continued)

. Diesel-water emulsions,such as Aquazole.

. Aftermarket diesel fueladditives, which containalcohols, organo-metallicadditives, or wateremulsifiers.

Caution

If the vehicle is accidentallyrefueled with gasoline, do notcontinue driving the vehicle.Driving the vehicle will damagethe fuel system. Have the vehicletowed to a qualified technician tohave the gasoline removed fromthe tank and fuel system. Refuelwith Ultra Low Sulfur Diesel fuel.It is also recommended to havethe fuel system flushed with UltraLow Sulfur Diesel, to ensure allgasoline is removed.

Some conditions, such as dirty fuel,may decrease fuel filter life and aCHANGE FUEL FILTER messagemay come on in the DriverInformation Center (DIC).

Climate Grade Diesel Fuels

At temperatures below 0 °C (32 °F),avoid using biodiesel blends above5% by volume. Using such a fuelmay cause fuel filter plugging,system gelling, and freezing, whichmay adversely impact vehiclestarting.

Severe winter grade diesel fuel,such as 1-D diesel fuel or Arcticgrade diesel fuel, can be used inextreme cold temperatures (below−18 °C or 0 °F); however, doing sowill reduce power and fuel economy.Avoid using severe winter grade fuelin warm or hot climates. It can resultin stalling, poor starting, anddamage to the fuel injection system.

Fuels improperly blended for coldtemperature operation may result inrestricted fuel filters. The vehicle isequipped with a fuel heating systemto prevent gelling or waxing of

conventional diesel fuel andbiodiesel blends, but may notprevent all cases.

In case of severe winter conditions,the fuel filter may become cloggedby wax naturally present in the fuel.To unclog it, move the vehicle to awarm garage area and allow thefilter to warm up. The fuel filter mayneed to be replaced. See Fuel FilterReplacement 0 36.

BiodieselBiodiesel is a renewable fuelproduced from vegetable oils oranimal fats that have beenchemically modified to make itcompatible with diesel fuel.

Caution

Do not use home-made biodieselor home test kits because thequality cannot be verified byapproved scientific methods. Donot use raw vegetable oil or otherunmodified bio-oils, fats,

(Continued)



Caution (Continued)

or blends of vegetable oil withdiesel. They could damage thefuel system and engine, anddamages would not be coveredby the vehicle warranty.

Biodiesel Blends

Fuels with a biodiesel content up to20% by volume may be used (e.g.,named B20). Only use biodieselblends up to 20% by volume thatcomply with your country’s orregion’s fuel standards.

Caution

Do not use blends containingmore than 20% biodiesel. Anyengine, fuel system, or exhaustafter-treatment system damagewould not be covered by thevehicle warranty.

As a renewable fuel, biodieselprovides some environmentalbenefits. However, biodiesel hasunique properties and needs to behandled differently than diesel fuel.Its use presents additional risks andmay not be appropriate in allsituations. Certain vehicle operatingmodes increase these risks andshould be avoided.

Biodiesel fuel quality degrades withtime and exposure to hightemperature quicker than Ultra LowSulfur Diesel fuel. More frequentrefueling provides the bestopportunity to have a supply of freshfuel. Storage at hot ambienttemperatures will acceleratebiodiesel degradation.

If the vehicle is not driven often anduses little fuel, or if it is stored forextended periods of time, avoid theuse of biodiesel blended fuelsabove 5% by volume. When thevehicle is stored for longer than onemonth, it should be run out ofbiodiesel to below one-quarter tank,

refueled with biodiesel-free fuel, anddriven several kilometers (miles)before storage.

Cold Weather OperationIn cold weather, the fuel filter maybecome clogged by wax naturallypresent in the fuel. To unclog it,move the vehicle to a warm garagearea and allow the filter to warm up.The fuel filter may need to bereplaced. See Fuel FilterReplacement 0 36.

At temperatures below 0 °C (32 °F),it is recommended to avoid usingbiodiesel blends above 5% blend.This blend may cause fuel filterplugging, system gelling, andfreezing that may affect vehiclestarting. You may need to turn theignition on and off a few timesbefore the vehicle will start. Also,idle the vehicle for a couple ofminutes before accelerating.

It is recommended to use Ultra LowSulfur No. 1-D diesel fuel or a blendof No. 1-D and No. 2-D diesel fuel toenhance vehicle operation in cold



weather at temperatures below 0 °C(32 °F). Use of No. 1-D diesel fuelmay lower the fuel economy. Foradditional information for better coldweather operation, see EngineHeater 0 21.

Water in FuelImproper fuel tank inspection orcleaning, or contaminated fuel fromsuppliers, can cause water to bepumped into the fuel tank along withthe diesel fuel. If a WATER IN FUELSERVICE REQUIRED messagedisplays, the water must be drainedimmediately.

{ Warning

Diesel fuel containing water is stillcombustible. You or others couldbe burned. If the fuel needs to bedrained, keep sparks, flames, andsmoking materials away from themixture.

Caution

Water in the diesel fuel cancorrode internal components ofthe fuel system and lead tosevere damage. It can alsosupport fungus or bacteriagrowth, which can damage thefuel system. Even with a dieselfuel biocide, the fuel system maystill need to be cleaned. Yourdealer can advise of theappropriate solution.

If the fuel tank needs to bepurged to remove water, see yourdealer or a qualified technician.Improper purging can damage thefuel system.

Water in Fuel Troubleshooting

If the WATER IN FUEL SERVICEREQUIRED message comes on:

ProblemRecommended

Action

Messagedisplays butgoes off duringthe ignitioncycle.

The fuel filter ispartially filledwith water. Drainthe water assoon aspossible. See"RemovingWater from theFuel Filter"following.



ProblemRecommended

Action

Messagedisplays andstays on.

Drain the fuelfilterimmediately.If no water canbe drained, andthe temperatureis belowfreezing, thenwater may befrozen in thefilter. Move thevehicle to awarm location tothaw the water,then drain thefuel. If water stilldoes not drain,see your dealer.

ProblemRecommended

Action

Immediatelyafter refueling,messagedisplays andstays on.

A large amountof water is in thefuel tank. Drainthe fuel filterimmediately.If the messagestays on orcomes back onwithoutrefueling, thenfuel tank purgingis required. Seeyour dealer.If the messagedisplays and theengine stalls orruns rough, donot drive untilthe watercontaminatedfuel is drained.

Caution

Driving with this message on candamage the fuel injection systemand the engine. If the messagecomes on right after a refuel,water was pumped into the fueltank. Turn off the engine anddrain the water immediately.

Removing Water from the FuelFilter

To drain water:

1. Turn the engine off and applythe parking brake.



2. Place a container under thefilter drain valve. The filter drainvalve is on the bottom of thefuel filter. The filter drain valveis under the vehicle on thedriver side, inside theframe rail.

3. Open the drain valve by turningit counterclockwise. Allow thefilter to drain until all of thewater has been removed.Close the valve.

4. Properly dispose of the watercontaminated fuel.

5. Start the engine and let it runfor a few minutes. During thedraining process, air may haveentered the fuel system. If theengine stalls, the fuel systemmay need to be primed. See“Fuel Priming” following.

Fuel Priming

For the fuel system to work properly,the fuel lines must be full of fuel.If air gets in, the fuel lines need tobe primed before operating thevehicle.

If air is present, the following mayhave happened:

. The vehicle ran out of fuel.

. The fuel filter was removed.

. The fuel lines were removed ordisconnected.

. The fuel filter water drain valvewas opened while the enginewas running.

Priming the Fuel System

There is an electric priming pumpthat will bring fuel to the engine andeliminate air in the fuel lines. Toprime the engine:

1. Correct any condition thatcaused the loss of prime.

2. Turn the ignition on for30 seconds. Do not start theengine. The fuel pump will startpriming.

3. Turn the ignition off, then backon, and crank the engine for15 seconds.

4. If the engine does not start,repeat Steps 2 and 3 until theengine starts.

If the engine does not startafter repeating Steps 2 and 3three times, turn the ignition offfor 60 seconds.

5. Repeat the above steps untilthe engine starts.

6. If the engine starts, but doesnot run smoothly, increase theengine speed slightly.



7. If the engine starts and runsbut stalls again, turn theignition off for 60 seconds.

8. When the engine starts, let itidle for a few minutes andcheck the filter for any leaks.

Running Out of FuelIf the engine has stalled due torunning out of fuel, try to restart it:

1. If parked on a level surface,add at least 3.8 L (1 gal) of fuel.Up to 18.9 L (5 gal) may beneeded if parked on a slope.

2. Follow the vehicle fuel systempriming procedure earlier inthis section to re-prime thesystem and restart the engine.

If the malfunction indicator lamp(check engine light) comes on dueto running out of fuel, it may take afew drive cycles to clear.

Fuel Filter Replacement

{ Warning

Diesel fuel is flammable. It couldstart a fire if something ignites it,and people could be burned. Donot let it get on hot engine parts,and keep matches or otherignition sources away.

The fuel filter is on the driver side,inside the frame rail.

To replace the fuel filter:

1. Drain any water from the filter.See “Removing Water from theFuel Filter” in Water in Fuel0 33.

Keep the engine off until theprocedure is completed.

2. Apply the parking brake.

3. Remove the filter element capby turning it counterclockwise.

4. Remove the filter element.If there is any dirt on the filtersealing surface, clean it off.

5. Install the new filter elementand o-ring.

6. Reinstall and tighten the filtercap to the housing.

7. Use the fuel filter primingprocedure to prime the fuelfilter. See “Fuel Priming” inWater in Fuel 0 33.



8. Start the engine and let it idlefor five minutes. Check the fuelfilter and air bleed valve forleaks.

9. Reset the fuel filter monitor.See Driver Information Center(DIC) 0 12.

Filling the TankAn arrow on the fuel gaugeindicates which side of the vehiclethe fuel door is on. See “FuelGauge” in the Owner’s Manual. Donot refill the diesel fuel and DieselExhaust Fluid (DEF) at thesame time.

{ Warning

Fuel vapors and fuel fires burnviolently and can cause injury ordeath.

(Continued)

Warning (Continued)

Follow these guidelines to helpavoid injuries to you and others:

. Read and follow all theinstructions on the fuelpump island.

. Turn off the engine whenrefueling.

. Keep sparks, flames, andsmoking materials awayfrom fuel.

. Do not leave the fuel pumpunattended.

. Avoid using electronicdevices while refueling.

. Do not re-enter the vehiclewhile pumping fuel.

(Continued)

Warning (Continued)

. Keep children away fromthe fuel pump and never letchildren pump fuel.

. Before touching the fillnozzle, touch a metallicobject to discharge staticelectricity from your body.

. Fuel can spray out if the fuelcap is opened too quickly.This spray can happen if thetank is nearly full, and ismore likely in hot weather.Open the fuel cap slowlyand wait for any hiss noiseto stop, then unscrew thecap all the way.



Double Cab Shown, Crew CabSimilar

Turn the fuel cap counterclockwiseto remove. When refueling, hang thefuel cap from the hook on the fueldoor. Fully insert and latch the fillnozzle, begin fueling.

{ Warning

Overfilling the fuel tank by morethan three clicks of a standard fillnozzle may cause:

(Continued)

Warning (Continued)

. Vehicle performance issues,including engine stalling anddamage to the fuel system.

. Fuel spills.

. Under certain conditions,fuel fires.

Diesel fuel can foam when filling thetank. The automatic pump nozzlemay shut off, even if the tank is notfull. Wait for the foaming to stop,and then fill the tank more slowly.Be careful not to spill fuel. Waitfive seconds after pumping beforeremoving the fill nozzle. Clean fuelfrom painted surfaces as soon aspossible. See Exterior Care 0 78.

Reinstall the cap by turning itclockwise until it clicks. Push thefuel door closed.

{ Warning

If a fire starts while you arerefueling, do not remove the fillnozzle. Shut off the flow of fuel byshutting off the pump or bynotifying the station attendant.Leave the area immediately.

Caution

If a new fuel cap is needed, besure to get the right type of capfrom your dealer. The wrong typeof fuel cap may not fit properlyand could damage the fuelsystem.



Accidental Refueling withGasoline

Caution

If the vehicle is accidentallyrefueled with gasoline, do notcontinue driving the vehicleexcept to get to a location whereit can be stopped safely. Drivingthe vehicle will damage theengine. Tow the vehicle forservice. Have the gasolineremoved from the tank and fuelsystem.

Filling a Portable FuelContainer

{ Warning

Filling a portable fuel containerwhile it is in the vehicle can causefuel vapors that can ignite eitherby static electricity or other

(Continued)

Warning (Continued)

means. You or others could bebadly burned and the vehiclecould be damaged. Always:

. Use approved fuelcontainers.

. Remove the container fromthe vehicle, trunk, or pickupbed before filling.

. Place the container on theground.

. Place the nozzle inside thefill opening of the containerbefore dispensing fuel, andkeep it in contact with the fillopening until filling iscomplete.

. Fill the container no morethan 95% full to allow forexpansion.

. Do not smoke, lightmatches, or use lighterswhile pumping fuel.

. Do not use electronicdevices while pumping fuel.

Trailer TowingWhen towing at high elevation onsteep uphill grades, consider thefollowing:

Engine coolant at higher elevationwill boil at a lower temperature thanat or near sea level. If the engine isturned off immediately after towingat high elevation on steep uphillgrades, the vehicle may show signssimilar to engine overheating. Toavoid this, let the engine run whileparked (preferably on level ground)with the transmission in P (Park)and the parking brake applied for atleast five minutes before turning theengine off. If the overheat warningcomes on, see Engine Overheating0 74.

Use the following chart to determinethe maximum the trailer can weigh,based upon your vehicle model andoptions.

All axles of the trailer must beequipped with brakes adequate forthe intended use. Trailer brakingequipment conforming to Canadian



Standards Association (CSA)requirement CAN3-D313, or itsequivalent, is recommended.

See “Trailer Towing” in the owner’smanual for kingpin weight and trailertongue weight information.

Weight of the Trailer Tongue

The tongue weight load (1) of anytrailer is very important because it isalso part of the vehicle weight. TheGross Vehicle Weight (GVW)includes the curb weight of thevehicle, any cargo carried in it, andthe people who will be riding in thevehicle as well as trailer tongueweight. Vehicle options, equipment,passengers, and cargo in thevehicle reduce the amount oftongue weight the vehicle can carry,which will also reduce the trailerweight the vehicle can tow.

The trailer tongue weight (1) shouldbe 10-15% of the total loadedtrailer (2).

Do not exceed the maximumallowable tongue weight for thevehicle. Choose the shortest hitchextension that will position the hitchball closest to the vehicle. This willhelp reduce the effect of trailertongue weight on the rear axle.

Trailer rating may be limited by thevehicle's ability to carry tongueweight. Tongue or kingpin weightcannot cause the vehicle to exceedthe GVWR (Gross Vehicle WeightRating) or the RGAWR (Rear Gross

Axle Weight Rating). See “TotalWeight on the Vehicle's Tires” in theowner’s manual.

After loading the trailer, weigh thetrailer and then the tongue,separately, to see if the weights areproper. If they are not, adjustmentsmight be made by moving someitems around in the trailer.

If a cargo carrier is used in thetrailer hitch receiver, choose acarrier that positions the load asclose to the vehicle as possible.Make sure the total weight,including the carrier, is no more thanhalf of the maximum allowabletongue weight for the vehicle or227 kg (500 lb), whichever is less.



Conversions andAdd-Ons

Power Take-Off (PTO)If equipped, the Power Take-Off(PTO) is a GM Upfitter integratedsystem that creates an auxiliarypower source for running add-onequipment, such as salt spreaders,snow plows, winches, and liftbuckets. It controls engine speed tovalues higher than normal base idle,PTO integral clutch engagement,and remote starting and shutdownof the engine.

PTO Switch

If equipped, there is an availablePTO switch in the auxiliaryswitchbank in one of the right sidepositions.

When installing PTO aftermarketequipment, the PTO wiring andoperation recommendationsprovided by the service manual andGM Upfitter documentation must bestrictly followed.

Refer to the bulletins in the GMUpfitter Integration websitewww.gmupfitter.com for the PTOOperating Description andApplication Guide.

{ Warning

Engine exhaust contains CarbonMonoxide (CO), which cannot beseen or smelled. Exposure to COcan cause unconsciousness oreven death. Never operate PTOin an enclosed area such as agarage or building that has nofresh air ventilation. See “EngineExhaust” in the owner’s manual.

{ Warning

If the key is in the ignition (KeyAccess) or the RKE transmitter isin the vehicle (Keyless Access)during Remote PTO operation,the vehicle can be shifted out ofP (Park). Even though PTO will

(Continued)



Warning (Continued)

be disengaged, depending onPTO Upfitter application, personalinjury or property damage mayresult from vehicle movement.Always remove the key from theignition or the RKE transmitterfrom the vehicle before operatingRemote PTO, unless the RemoteOperation In-Cab Enable featureis used.

Primary PTO Operating Modes

PTO modes of operation are:

. Preset

Stationary operation only: In-cabcontrol is standard, remotecontrol is available. Presetspeed control is standard.

. Variable

Available in in-cab control and inremote control.

. Mobile

In-cab control only. Variablespeed control only available.

. Operator Selectable In-CabMode (OSIM)

In-cab operation only.

OSIM is for vehicles that requireboth stationary and mobilemodes. OSIM is available via theGM Service Tool only. During theconfiguration of OSIM, twomodes must be paired:stationary preset and mobile,or stationary variable andmobile. During activation ofOSIM, one of the two modeswithin the pre-configured pairingmust be selected. If an OSIMmode is not selected, PTO willnot operate.

OSIM modes of operation are:

‐ Stationary

The configuration may bestationary preset or stationaryvariable.

‐ Mobile

The configuration isvariable only.

Selection between OSIMpairings is not available.

Remote modes are notavailable.

The factory default programmingenables in-cab control. Forstationary modes, the GM ServiceTool can reprogram the system toallow for remote control and disablethe in-cab control.

All PTO modes provide for enginerpm control and PTO clutch control.

All PTO modes provide for safetyinterlocks for PTO loaddisengagement.

Remote PTO modes provide forremote engine starting andshutdown.

Stationary in-cab and Remote PTOmodes provide for engine shutdowndue to critical engine conditions, aswell as a timed engine shutdownfeature.



Preset PTO

Preset Enable Conditions –In-Cab Operation

To enable PTO:

1. With the engine running, shiftthe vehicle into P (Park) andset the parking brake. Do notpress the brake pedal.

2. Confirm cruise control is off.

3. Press and release the PTOin-cab switch below the climatecontrols in the center stack.The PTO clutch will engage.The PTO indicator light willflash rapidly until the enginereaches the PTO StandbySpeed and it will then be onsteady.

4. Once the PTO Standby Speedis reached, use SET− and+RES on the cruise control toreach the Set 1 or Set 2 PTOengine speeds.

The accelerator pedal isdisabled in standardconfiguration. The acceleratorpedal may be used to override

the PTO present speeds ifconfigured by the GM ServiceTool. The PTO must beoperated below the Max PTOEngine Speed configured.

Factory Default PTO EngineSpeeds

Standby 900 rpm

Set 1 (SET−) 1200 rpm

Set 2 (+RES) 1900 rpm

The first time PTO is used:

1. The PTO Control setting on theGM Service Tool isprogrammed to Interior ModePTO Switch.

2. Check the correct operation ofthe default PTO presetstationary mode to observe thethree idle up speeds. The PTOfunction should be confirmedbefore any wiring modificationsare done or anyreprogramming is attempted.See your dealer if the defaultpresets are not functioningproperly.

3. When the PTO indicator light iseither flashing or on solid, thePTO clutch will be activated.

Preset Enable Conditions –Remote Operation

This requires programming with theGM Service Tool and remote switchpanel provided by GM Upfitter.


2. Set the parking brake and shiftthe transmission into P (Park).

3. Turn the ignition off or removethe ignition key, if equipped.

4. Confirm the hood is closed.

5. From outside the vehicle, pressand release the Remote PTOArm switch.

6. Within five seconds, open andclose the Remote PTO EngineStart/Shutdown switch.

7. The horn will chirp, and enginestarting will be initiated. ThePTO system will then elevateengine rpm to PTO Standby



Speed and engage the PTOclutch. Park lamps willcome on.

8. The Remote PTO Set switchcan now be used to set thePTO Set 1 and Set 2 enginespeeds.

The accelerator pedal is disabledwhen Remote PTO operation isselected.

{ Warning

If the key is in the ignition (KeyAccess) or the RKE transmitter isin the vehicle (Keyless Access)during Remote PTO operation,the vehicle can be shifted out ofP (Park). Even though PTO willbe disengaged, depending onPTO Upfitter application, personalinjury or property damage mayresult from vehicle movement.Always remove the key from theignition or the RKE transmitterfrom the vehicle before operating

(Continued)

Warning (Continued)

Remote PTO, unless the RemoteOperation In-Cab Enable featureis used.

Preset Enable Conditions –Remote Operation In-Cab Enable


To start remote operation in-cab:

1. With the engine running, shiftthe vehicle into P (Park),release the brake pedal, andset the parking brake.



4. Press and release the in-cabPTO switch.

5. The horn will chirp, the PTOclutch will engage, and theengine will advance to the PTOStandby Speed. Park lampswill come on.

6. The Remote PTO Set switchmay be used to select PTO Set1 and Set 2 engine speeds.


The vehicle may be exited.

With the Remote Operation In-CabEnable feature remote PTOoperation may be ended bypressing the brake pedal, at whichtime the PTO clutch disengages andthe engine returns to base idlespeed. The vehicle can be drivenafter the parking brake is released.

Preset Enable Conditions –Operator Selectable In-CabMode (OSIM)

This requires programming with theGM Service Tool and requirespairing OSIM stationary preset withOSIM mobile mode. If OSIM pairinghas been configured, initiate OSIMpreset operation:






4. Press and release the in-cabPTO switch. The PTO indicatorlight will flash slowly.

5. Within 10 seconds, press andrelease SET− on the cruisecontrol.

. The PTO clutch engageswhen the PTO operation isinitiated by the switch input.

. The first elevated enginespeed, PTO StandbySpeed, is intended asverification that the systemis active and ready to go toa working speed. Thisspeed can be modified to aworking speed with the GMService Tool. The upperlimit for PTO StandbySpeed is 1500 rpm.

6. The PTO clutch will engageand the PTO indicator light willchange to solid when theengine speed reaches the PTOStandby Speed. Press andrelease SET− on the cruisecontrol to select the PTO Set 1speed. Press and release+RES on the cruise control toselect the PTO Set 2 speed.

Variable PTO

Variable Enable Conditions –In-Cab Operation

This requires programming with theGM Service Tool.

To enable PTO:

1. With the engine running, shiftthe vehicle into P (Park),release the brake pedal, andset the parking brake. Makesure Cruise Control is off.

2. Press and release the PTOin-cab switch below the climatecontrols in the center stack.The PTO clutch will engage.The PTO indicator light willflash rapidly until the engine

reaches the PTO StandbySpeed and it will then be onsteady.

3. Once PTO Standby Speed isreached, SET− and +RES onthe cruise control can be usedto tap up and tap down theengine speed. Factory settingfor the tap step is 100 rpm andthe setting for the ramp rate is148 rpm/sec. The GM ServiceTool can enable changing thedefault value for tap stepthrough vehiclepersonalization. The defaultvalues for both tap step andramp rate can be changed withthe GM Service Tool. Theaccelerator pedal is disabled,and cannot be used to controlPTO engine speed.

Variable Enable Conditions –Remote Operation

This requires programming with theGM Service Tool and theappropriate remote switch panelprovided by GM Upfitter.




2. Set the parking brake and shiftthe transmission into P (Park).

3. Turn the ignition off or removethe ignition key, if equipped.


5. From outside the vehicle, pressand release the Remote PTOArm switch.

6. Within five seconds, open andclose the Remote PTO EngineStart/Shutdown switch.

7. The horn will chirp, and thenengine starting will beautomatically initiated. ThePTO system will engage thePTO clutch and then elevateengine rpm to PTO StandbySpeed.

{ Warning

If the key is in the ignition (KeyAccess) or the RKE transmitter isin the vehicle (Keyless Access)during Remote PTO operation,the vehicle can be shifted out of

(Continued)

Warning (Continued)

P (Park). Even though PTO willbe disengaged, depending onPTO Upfitter application, personalinjury or property damage mayresult from vehicle movement.Always remove the key from theignition or the RKE transmitterfrom the vehicle before operatingRemote PTO, unless the RemoteOperation In-Cab Enable featureis used.

Variable Enable Conditions –Remote Operation In-Cab EnableStarting Remote Operation fromIn-Cab





4. Press and release the PTOin-cab switch.

5. The horn will chirp, the PTOclutch will engage, and theengine will advance to the PTOStandby Speed.

The vehicle may be exited.


. The desired engine operatingspeed can now be reached.Switches or potentiometerengine rpm controls areavailable, depending on whichone was installed.

‐ Switches – The Remote PTOSet and Resume switches canbe used to tap up and tapdown to the desired enginespeed.

‐ Potentiometer – A RemotePTO Throttle Potentiometercan be used as a continuousvariable throttle control to dialin the desired engine speed.



Press the brake pedal to endremote PTO operation. The PTOclutch disengages and the enginereturns to base idle speed. Thevehicle can be driven after theparking brake is released.

Variable Enable Conditions– OSIM

This requires programming with theGM Service Tool and specificpairing of stationary variable andmobile modes. Remote operation isnot available.

If OSIM pairing has beenconfigured, initiate OSIM stationaryvariable operation:




4. Press and release the PTOin-cab switch. The PTOindicator light will flash slowly.

5. Within 10 seconds, press andrelease SET− on the cruisecontrol. The PTO clutch willengage and the engine speedwill advance to the PTOStandby Speed. The PTOindicator light will change tosolid.

6. Tap +RES and SET− on thecruise control for the desiredoperating speed.

. The first elevated engine speed,PTO Standby Speed, is intendedas verification that the system isactive and ready to go to aworking speed.

. The engine speeds can beadjusted between the low ofPTO Standby Speed and thehigh of PTO Max Engine Speedlimits. Both values can bemodified with the GM ServiceTool. Based on the value chosenfor PTO Max Engine Speed, thePTO menu in the center stackmay show speeds that are notavailable.

. Factory setting for the tap step is100 rpm and the setting for ramprate is 148 rpm/sec. The valuefor tap step can be modifiedthrough vehicle personalization.The values for both tap step andramp rate can be changed withthe GM Service Tool.

. Refer to the service manual orgo to the GM Upfitter Integrationwebsite www.gmupfitter.com.

Mobile PTO

Mobile Enable Conditions –In-Cab Operation Only

This requires programming with theGM Service Tool.

1. The engine must be running.

2. The parking brake must bereleased.


4. Engine rpm must be less than1500 rpm.

5. Shift the transmission to L1,L2, L3, L4, or L5.



6. Tap the brake pedal but do notcontinue pressing the brakepedal.

7. Keep the driver door closed.The driver door can be keptopen if reconfigured using theGM Service Tool. Seewww.gmupfitter.com.

8. Press and release the PTOin-cab switch below the climatecontrols in the center stack.Within 10 seconds press andrelease +RES on the cruisecontrol. The PTO indicator lightwill flash slowly betweenpresses. The PTO clutch willengage and the PTO indicatorlight will flash rapidly until PTOreaches Standby Speed, andthen the light will becomesteady. The engine speed willremain at the current throttlesetting or advance to PTOStandby Speed, whichevervalue is greater. If the enginespeed is above 1500 rpm(configurable), the PTO clutch

will not engage. PTO can beengaged when the enginespeed drops below 1500 rpm.

9. Once engaged, if additionalengine speed is desired, useeither the cruise control or theaccelerator pedal to temporarilyadjust the engine speed.

‐ +RES or SET− on the cruisecontrol can be used to tap upor down, or if continuouslyheld to ramp up or down, tothe desired operating speed.Top limit is PTO Max EngineSpeed, default 2100 rpm andprogrammable to 3100 rpm.Lower limit is PTO StandbySpeed, default 900 rpm withprogram range from baseidle to 900 rpm.

‐ The accelerator pedal can beused to achieve the desiredspeed. When the desiredspeed is reached, use SET−on the cruise control tocapture and maintain that

speed. Normal tap up andtap down can then be usedto fine tune the setting.

In Mobile PTO mode, the vehiclespeed reached is the result of thecurrent engine speed requested andthe transmission gear rangeselected. The gears available forselection are L1 through L5. Thetransmission may limit the selectionof a higher gear until a minimumspeed for that gear is reached.Attempts to up-shift higher than L5will be denied by the transmissionsystem.

Mobile Enable Conditions –Operator Selectable In-CabMode (OSIM)

This requires programming with theGM Service Tool and specificpairing mobile mode with eitherstationary preset or variable.Remote operation is not available.

See “Mobile PTO” previously in thissection.



PTO System DisengageConditions

Preset or Variable StationaryModes – In-Cab Operation

To disengage PTO, do one of thefollowing:

. Press the brake pedal. Theengine returns to base idle, butthe PTO clutch remainsengaged. The PTO indicatorlight will flash slowly indicatingthat a PTO set speed is stillstored in memory. When thebrake pedal is released, theengine speed will return to curbidle. A press and release of+RES on the cruise control willrestore engine rpm to the lastPTO set speed. The PTOsystem can also be programmedto return engine rpm to the PTOStandby Speed setting.

. Press* on the cruise control.The engine returns to base idle,but the PTO clutch remainsengaged. The PTO indicatorlight will flash slowly indicatingthat a PTO set speed is still

stored in memory. Pressing+RES on the cruise control willrestore engine rpm to the lastPTO set speed.

. Press the PTO in-cab switch.The PTO clutch disengages andthe engine returns to base idle.The PTO indicator light will turnoff, indicating the PTO clutch isdisengaged and the stored setspeed has been cleared frommemory.

Stationary Modes (Preset orVariable) – Remote Control

To disengage PTO:

. Open the Remote PTO EngineStart/Shutdown switch. The PTOclutch disengages and theengine will stop.

. If equipped, press the PTOEmergency Stop switch. ThePTO clutch disengages and theengine will stop. Refer to thebulletins in the GM UpfitterIntegration websitewww.gmupfitter.com for the

Power Take Off (PTO) operatingdescription and applicationguide.

. For key access vehicles, turn theignition on and press the brakepedal. For keyless accessvehicles, hold the push buttonstart for two seconds. Press thebrake pedal. The PTO clutchdisengages and the enginereturns to base idle speed.

Stationary Modes will alsodisengage if:

. Vehicle movement is detected.

. The parking brake is released.

. The transmission is shifted outof P (Park).

. The ignition is cycled from onto off.

. The PTO feedback signal is lostindicating the load is disengagedif used. Seewww.gmupfitter.com.

. Cruise control becomes enabled.


50 Driving and Operating. Timed auto-engine shutdown:

PTO must be operational for thisfunction to be active.

. The engine is shut down basedon critical engine or PTO systemfault conditions: This feature willshut down the engine when PTOis operating if a critical enginecondition such as low oil, low oilpressure, hot engine, hottransmission, low fuel, or DieselParticulate Filter regeneration isdetected by the vehicle system.If PTO operation is continuedwhen critical engine conditionsare present, a horn chirpwarning will occur after 30–60 seconds. The engine will shutdown two minutes after the hornwarning. The engine can berestarted with the ignition key orwith the Remote PTO enginestart controls or by push buttonstart. The horn warning andengine shutdown will againoccur if the critical enginecondition is still present.

. Maximum engine torque limithas been reached.

Resume memory speed is clearedfor the above actions.

When Remote PTO engine startinghas been initialized with the ignitionkey in the RUN position, the shiftlever will remain locked. A shift outof P (Park) will not be allowed whilethe engine is running and PTO isactive, until one of the followingactions is taken:

. Press the brake pedal. PTO willdisengage. Engine will run atidle speed and shift lever can beshifted from P (Park).

. Press the PTO in-cab switch,only if the PTO in-cab RemoteStart/Stop feature is enabled.This requires programming withthe GM Service Tool. PTO willdisengage and shift lever can beshifted from P (Park).

Mobile Mode

To disengage PTO:

. Press the brake pedal. The PTOsystem releases control ofengine speed, but the PTOclutch remains engaged. The

engine will return to base idleunless the accelerator pedal ispressed. The PTO clutchremains engaged. The PTOindicator light will flash slowlyindicating that a PTO set speedis still stored in memory. Uponreleasing the brake, the factorydefault programming is for theengine speed to remain at curbidle awaiting an input from +RESon the cruise control to restoreengine rpm to the last PTO setspeed. The system can also beprogrammed to return enginerpm to the PTO Standby Speedsetting.

. Press* on the cruise control.The engine returns to base idle,but the PTO clutch remainsengaged. The PTO indicatorlight will flash slowly indicatingthat a PTO set speed is stillstored in memory. Pressing+RES on the cruise control willrestore engine rpm to the lastPTO set speed.


Driving and Operating 51. Press the PTO in-cab switch.

The PTO clutch disengages andthe engine returns to base idle.The PTO indicator light will turnoff, indicating the PTO clutch isdisengaged and the stored setspeed has been cleared frommemory.

Mobile Mode will also disengage if:

. PTO feedback input is lost. Theengine speed is returned to thePTO Standby speed setting andthe load is still engaged. This isconfigurable with the GMService Tool.

. Vehicle Speed exceeds MaxVehicle Speed. Factory defaultsetting = 94 km/h (58 mph). PTOwill re-engage and advance tothe last engine speed stored inmemory when both the vehiclespeed is reduced below 94 km/h(58 mph) and the engine speedramps down below the maximumPTO engagement speed (1500rpm factory default setting).

. Engine Speed exceeds MaxEngine Speed for more than15 seconds. Factory defaultsetting = 2100 rpm.

. 5 on the cruise control ispressed.

. The parking brake is applied.

. Maximum engine torque limithas been reached.

Resume memory speed is clearedfor the above actions.

Although the PTO system attemptsto limit accelerator and PTO switchinputs to comply with maximumspeed and/or rpm parameters, somevehicle operating conditions such asdownhill acceleration can cause thevehicle speed or engine rpm toexceed these limits. In those cases,the PTO system may disengage.

Operator Selectable In-CabMode (OSIM)

To disable OSIM Stationary PTO:

. Press and release the PTOin-cab switch.

To disable OSIM Mobile PTO:

. Press and release the PTOin-cab switch.

Prolonged or Extended PTOOperation

When operating the vehicle instationary PTO mode, the DieselParticulate Filter (DPF) will continueto filter the exhaust and build upsoot. The engine control system,depending on the speed and loadbeing applied by the PTO, may notbe able to generate enough energyor adequate heat needed toautomatically clean or regeneratethe DPF. If manual regeneration isnot initiated, continued operationunder conditions that do not alloweffective regeneration or cleaningwill eventually plug the DPF andresult in reduced power. TheENGINE POWER IS REDUCEDDriver Information Center (DIC)message and malfunction indicatorlamp will display. See your dealerfor service. To prevent this,frequently monitor the vehicle duringstationary PTO operation, and pay



attention to horn chirps and/or theCLEAN EXHAUST FILTER SEEOWNER MANUAL NOW DICwarning messages. If the DICmessage is displayed during PTOoperation, see Diesel ParticulateFilter 0 22 for information on how toclean or regenerate the DPF.

PTO Operational SpeedControl

Variable PTO operational speedcontrol provides the followingfunctions:

Cruise Control SET− (In-Cab) orRemote PTO Set 1 Switch

SET : When PTO is engaged pressand hold the accelerator to obtainthe desired engine speed, thenpress and release SET− on thecruise control. The current enginespeed will be maintained. Thisaction can be repeated as desiredto capture a higher rpm value. ThePTO set speed cannot exceed 3100rpm, or the PTO Max Engine Speedconfigured.

TAP DOWN : Press and releaseSET− on the cruise control toreduce the engine speed bydecrements of 100 rpm. The tapdown engine speed decrements canbe adjusted by the GM Service Tool.In Remote Mode use Set 1 Switchto reduce engine speed. Adjustmentof tap down engine speeddecrements can be done throughvehicle personalization.

COAST : Press and hold SET− onthe cruise control to reduce the rpmat 148 rpm/sec until the desiredengine speed is reached or until theinitial PTO Standby Speed isreached. Use Set 1 Switch inRemote Mode. The speed changewill happen after three seconds ofholding SET− or Set 1 switch.

In-Cab Cruise Control +RES orRemote PTO Set 2 Switch

RESUME : After a PTO set speedhas been met, a Resume Speedmessage is retained, after applyingthe brake pedal or pressing* on

the cruise control . Engine speedwill reduce to basic idle speed. The

PTO indicator light will flash slowlyindicating the previous PTO setspeed has been retained in memory.Press and release +RES on thecruise control to resume theprevious PTO set speed.

TAP UP : Press and release +RESon the cruise control to increase theengine speed by increments of 100rpm. The tap up engine speedincrements can be adjusted by theGM Service Tool. In Remote Modeuse Set 2 Switch to increase enginespeed. Adjustment of tap downengine speed increments can bedone through vehiclepersonalization.

ACCEL : Press and hold +RES onthe cruise control to increase therpm by 148 rpm/sec until thedesired engine speed is reached oruntil the maximum allowable PTOset speed is reached. The speedchange will happen afterthree seconds of holding +RES orSet 2 switch. Alternatively, theengine speed acceleration can beadjusted by the GM Service Tool.



Factory Preset Parameters

The following table lists the factory preset parameters. These may be altered by the GM Service Tool to configure thevarious PTO features.

ProgrammableParameters

Factory Setting Minimum Value Maximum Value

PTO Option Configuration VEHICLE STATIONARY,PRESET SPEED

VEHICLE STATIONARY,PRESET SPEED

VEHICLE STATIONARY,VARIABLE SPEEDVEHICLE MOBILE,VARIABLE SPEED

PTO Control In-Cab PTO Mode In-Cab PTO Mode, RemotePTO Mode, OperatorIn-Cab SelectableMode (OSIM)

Type of Set SwitchOperation

MOMENTARY MOMENTARY LATCHING

PTO SET 1 Engine SpeedAfter PTO On

DISABLED DISABLED ENABLED

Interlock or RedundantEmergency Stop Feedback






Keep PTO Clutch Engagedduring Braking or upon

Pressing *

ENABLED DISABLED ENABLED

Action after Brake IsReleased

RETURN TO BASEIDLE rpm

RETURN TO BASEIDLE rpm

RETURN TOSTANDBY rpm

Max. vehicle speed may belimited to 40 km/h (25 mph)if this is programmed withthe GM Service Tool. Afterreverting back to RETURNTO BASE IDLE rpm usingthe GM Service Tool, Max.vehicle speed is also to beset to required speed.

Set Low Fuel Level forEngine Shutdown

15% 0% 25%

Engine Run Time with PTOActive Timer


Engine Run Time whilePTO Is Active

420 min 10 min 3480 min

PTO Max. Engine Speed 2100 rpm 1100 rpm 3100 rpm





Min. Engine Speed forPTO Engagement

500 rpm 500 rpm 1000 rpm

Max. Engine Speed forPTO Engagement

1500 rpm 1000 rpm 1800 rpm

PTO Standby rpm 900 rpm 700 rpm 1500 rpm

PTO Set Speed 1 1200 rpm 1100 rpm 2900 rpm

PTO Set Speed 2 1900 rpm 1700 rpm 3100 rpm

Engine Speed Tap Step 100 rpm 4 rpm 500 rpm

Engine Speed Ramp Rate 148 rpm/s 4 rpm/s 148 rpm/s

Maximum Vehicle Speed 94 km/h (58 mph) 30 km/h (19 mph) 94 km/h (58 mph)

Minimum RemotePotentiometer Threshold

2% 0% 50%

Maximum RemotePotentiometer Threshold

95% 50% 100%

Remote Set SwitchTransition to Low Voltage(<33% of Ignition Voltage)

SET SPEED 1 STANDBY SPEED, SET SPEED 1, or SET SPEED 2





Remote Set SwitchTransition to Open State(>33% of Ignition, and

<67% of Ignition Voltage)

PTO STANDBY STANDBY SPEED, SET SPEED 1, or SET SPEED 2

Remote Set SwitchTransition to High Voltage(>67% of Ignition Voltage)

SET SPEED 2 STANDBY SPEED, SET SPEED 1, or SET SPEED 2

Horn Chirps during aRemote Start Event


Standby Speed Menu ENABLED DISABLED ENABLED

Set 1 Speed Menu(In Stationary Preset)


Set 2 Speed Menu(In Stationary Preset)


Engine Run ShutdownTime Menu

(In Stationary Preset)






Engine Speed TapStep Menu

(In Stationary Variable andMobile)


Remote Set Switch SpeedControl


Remote Throttle SpeedControl


Remote Engine Start DISABLED DISABLED ENABLED

Remote Engine Shutdown DISABLED DISABLED ENABLED

Throttle Override ENABLED DISABLED ENABLED

Throttle Override Timer 10 Minutes 1 Minute 13 Minutes

Driver Door Status Usage ENABLED DISABLED ENABLED

Remote PTO In CabControl




If the PTO factory presetparameters do not match thesettings described above, then theymay have already been altered tosatisfy the requirements of theinstalled PTO system and bodyequipment.

The following PTO settings are alsooffered through vehiclepersonalization, which can beenabled by your dealer. Theseinclude the following parameters:

. PTO Standby rpm

. PTO Set 1 Speed

. PTO Set 2 Speed

. Tap Step Speed

. PTO Engine Run Timer

Driver Information Center (DIC)Warning Messages

If the PTO indicator light does notremain on, then not all PTOenabling conditions have been met.One or more DIC messages maydisplay if the PTO will not engageand the appropriate action must betaken.

In addition, the PTO indicator lightwill come on when all conditionsrequired to engage PTO have notbeen met. When enabling PTO, thePTO indicator light will turn on, thenturn off after one second. Undernormal operating conditions, thePTO indicator light will remain onthroughout the PTO operating cycle.

Additional in-vehicle PTO moduleinformation can be accessed by thedealer. Also see the service manualfor more information.

Your dealer can access Service Toolinformation to determine why PTOmay not engage and why PTO mayunexpectedly disengage due tosystem conditions.

See www.gmupfitter.com forinformation on the installation ofwiring and programming for PTOaftermarket equipment.

Diesel Particulate FilterCleaning during PTOOperation

This feature is only available onfleet and commercial vehicles. Toverify that the vehicle has thisfeature, see www.gmupfitter.com tocontact the GM Upfitter IntegrationGroup.

If equipped, this feature allows formanual cleaning/regeneration of theDiesel Particulate Filter (DPF) whenit is unable to clean itself. It may benecessary to perform a manualregeneration if driving conditions —such as extended slow speed,stop-and-go traffic, extended idles,short drive cycles, or stationary PTOoperation — prevent DPFself-cleaning.

Manual regeneration can only beused when the DPF has become atleast 90% full. In PTO stationarysession when DPF is in thiscondition, one minute of horn chirpsis initiated as a warning to theoperator to look for the DICmessage and take action for Manual



Regeneration. At 100% full, it willattempt to automatically self-clean ifproper driving conditions are met.The DPF will clean itself if thevehicle can be driven above50 km/h (30 mph) for about30 minutes.

Manual regeneration can be usedduring a stationary PTO session.However it is strongly recommendedthat the exhaust filter be cleanedbefore continuous PTO. If manualregeneration is operatingconcurrently with PTO then the PTOsystem will retain control of theengine speed. Low PTO enginespeeds will cause regeneration totake longer. To initiate a manualDPF regeneration, see “ManualRegeneration of Diesel ParticulateFilter” under Diesel Particulate Filter.


60 Vehicle Care

Vehicle Care

General InformationAccessories andModifications . . . . . . . . . . . . . . . . . 60

Vehicle ChecksEngine CompartmentOverview . . . . . . . . . . . . . . . . . . . . . 62

Engine Oil . . . . . . . . . . . . . . . . . . . . . 63Engine Oil Life System . . . . . . . . 66Automatic TransmissionFluid . . . . . . . . . . . . . . . . . . . . . . . . . 66

Engine Air Filter Life System . . . 66Engine Air Cleaner/Filter . . . . . . . 67Cooling System (Engine) . . . . . . 69Cooling System (LowTemperature CoolingCircuit) . . . . . . . . . . . . . . . . . . . . . . . 72

Engine Overheating . . . . . . . . . . . . 74Engine Fan . . . . . . . . . . . . . . . . . . . . 76

Electrical SystemEngine Compartment FuseBlock . . . . . . . . . . . . . . . . . . . . . . . . . 77

Appearance CareExterior Care . . . . . . . . . . . . . . . . . . 78

General Information

Accessories andModificationsAdding non-dealer accessories ormaking modifications to the vehiclecan affect vehicle performance andsafety, including such things asairbags, braking, stability, ride andhandling, emissions systems,aerodynamics, durability, andelectronic systems like antilockbrakes, traction control, and stabilitycontrol. These accessories ormodifications could even causemalfunction or damage not coveredby the vehicle warranty.

Damage to vehicle componentsresulting from modifications or theinstallation or use of non-GMcertified parts, including controlmodule or software modifications, isnot covered under the terms of thevehicle warranty and may affectremaining warranty coverage foraffected parts.

GM Accessories are designed tocomplement and function with othersystems on the vehicle. See yourdealer to accessorize the vehicleusing genuine GM Accessoriesinstalled by a dealer technician.

See the warranty manual.

Aftermarket EnginePerformance EnhancementProducts and Modifications

Some aftermarket engineperformance products andmodifications promise a way toincrease the horsepower and torquelevels of the vehicle's powertrain.You should be aware that theseproducts could have harmful effectson the performance and life of theengine, exhaust emission system,transmission, and drivetrain. Theengines, transmissions, anddrivetrains have been designed andbuilt to offer industry leadingdurability and performance in themost demanding applications.Engine power enhancementproducts may enable the engine tooperate at horsepower and torque


Vehicle Care 61

levels that could damage, createfailure, or reduce the life of theengine, engine emission system,transmission, and drivetrain.Damage, failure, or reduced life ofthe engine, transmission, emissionsystem, drivetrain, or other vehiclecomponents caused by aftermarketengine performance enhancementproducts or modifications might notbe covered under the vehiclewarranty.


62 Vehicle Care

Vehicle Checks

Engine Compartment Overview


Vehicle Care 63

1. Remote Negative (−) Terminal

2. Remote Positive (+) Terminal

3. Battery

4. Engine Air Cleaner/Filter

5. Engine Fan (Out of View)

6. Engine Oil Fill Cap

7. Engine Oil Dipstick

8. Auxiliary Battery

9. Low Temperature CoolingCircuit Coolant Reservoir andPressure Cap

10. Brake Fluid Reservoir

11. Engine Compartment FuseBlock

12. Engine Coolant Surge Tankand Pressure Cap

13. Auxiliary Fuse Block

14. Windshield Washer FluidReservoir

Engine OilTo ensure proper engineperformance and long life, carefulattention must be paid to engine oil.

Following these simple, butimportant steps will help protectyour investment:

. Use engine oil approved to theproper specification and of theproper viscosity grade. See“Selecting the Right Engine Oil”in this section.

. Check the engine oil levelregularly and maintain theproper oil level. See “CheckingEngine Oil” and “When to AddEngine Oil” in this section.

. Change the engine oil at theappropriate time. See “EngineOil Life System” in the owner’smanual.

. Always dispose of engine oilproperly. See “What to Do withUsed Oil” in this section.

Checking Engine Oil

Check the engine oil level regularly,every 650 km (400 mi), especiallyprior to a long trip. The engine oildipstick handle is a loop. SeeEngine Compartment Overview 0 62for the location.

{ Warning

The engine oil dipstick handlemay be hot; it could burn you.Use a towel or glove to touch thedipstick handle.

If a low oil Driver Information Center(DIC) message displays, check theoil level.

Follow these guidelines:

. To get an accurate reading, parkthe vehicle on level ground.Check the engine oil level afterthe engine has been off for atleast two hours. Checking theengine oil level on steep gradesor too soon after engine shutoffcan result in incorrect readings.Accuracy improves whenchecking a cold engine prior tostarting. Remove the dipstickand check the level.

. If unable to wait two hours, theengine must be off for at least15 minutes if the engine iswarm, or at least 30 minutes if


64 Vehicle Care

the engine is not warm. Pull outthe dipstick, wipe it with a cleanpaper towel or cloth, then push itback in all the way. Remove itagain, keeping the tip down, andcheck the level.

When to Add Engine Oil

If the oil is below the cross-hatchedarea at the tip of the dipstick andthe engine has been off for at least15 minutes, add 1 L (1 qt) of therecommended oil and then recheckthe level. See “Selecting the RightEngine Oil” later in this section foran explanation of what kind of oil touse. For engine oil crankcasecapacity, see Capacities andSpecifications 0 89.

Caution

Do not add too much oil. Oillevels above or below theacceptable operating rangeshown on the dipstick are harmfulto the engine. If the oil level isabove the operating range (i.e.,the engine has so much oil thatthe oil level gets above thecross-hatched area that showsthe proper operating range), theengine could be damaged. Drainthe excess oil or limit driving ofthe vehicle, and seek a serviceprofessional to remove theexcess oil.

See Engine Compartment Overview0 62 for the location of the engineoil fill cap.

Be sure to add enough oil to put thelevel somewhere in the properoperating range. Push the dipstickall the way back in when through.

Selecting the Right Engine Oil

Specification

Oils designated as API CJ-4 orCK-4 are required for the vehicle.The CJ-4 or CK-4 designation canappear either alone or incombination with other AmericanPetroleum Institute (API)designations, such as API CJ-4/SL.These letters show API levels ofquality.


Vehicle Care 65

American Petroleum Institute (API)Symbol

This doughnut-shaped logo(symbol) is used on most oilcontainers to help you select thecorrect oil. It means that the oil hasbeen certified by the AmericanPetroleum Institute.

Look for this on the oil container,and use only those oils that displaythis logo.

Caution

Use only engine oils that have thedesignation CJ-4 or CK-4 for thediesel engine. Failure to use therecommended oil can damage theDPF and result in engine damagenot covered by the vehiclewarranty.

Viscosity Grade

Use SAE 15W-40 viscosity gradeengine oil.

When it is very cold, below −18 °C(0 °F), use SAE 5W-40 to improvecold starting. These numbers on theoil container show its viscosity,or thickness.

When selecting an oil of theappropriate viscosity grade, alwaysselect an oil of the correctspecification. See “Specification”earlier in this section.

Engine Oil Additives/Engine OilFlushes — API

Do not add anything to the oil. Therecommended oils with the APIservice symbol are all that isneeded for good performance andengine protection.

Engine oil system flushes are notrecommended and could causeengine damage not covered by thevehicle warranty.

What to Do with Used Oil

Used engine oil contains certainelements that can be unhealthy foryour skin and could even causecancer. Do not let used oil stay onyour skin for very long. Clean yourskin and nails with soap and water,or a good hand cleaner. Wash orproperly dispose of clothing or rags


66 Vehicle Care

containing used engine oil. See themanufacturer's warnings about theuse and disposal of oil products.

Used oil can be a threat to theenvironment. If you change yourown oil, be sure to drain all the oilfrom the filter before disposal. Neverdispose of oil by putting it in thetrash or pouring it on the ground,into sewers, or into streams orbodies of water. Recycle it by takingit to a place that collects used oil.

Engine Oil Life SystemThe engine oil life system calculatesengine oil life based on vehicle useand displays the CHANGE ENGINEOIL SOON message when it is timeto change the engine oil and filter.The oil life system should be resetto 100% only following an oilchange. See “Engine Oil LifeSystem” in the owner’s manual.

Automatic TransmissionFluid

When to Check and ChangeAutomatic Transmission Fluid

It is usually not necessary to checkthe transmission fluid level. The onlyreason for fluid loss is atransmission leak or overheatedtransmission. This vehicle is notequipped with a transmission fluidlevel dipstick. There is a specialprocedure for checking andchanging the transmission fluid inthese vehicles. Because thisprocedure is difficult, this should bedone at your dealer. Contact yourdealer for additional information orrefer to the service manual for theprocedure.

Caution

Use of the incorrect automatictransmission fluid may damagethe vehicle, and the damage maynot be covered by the vehicle

(Continued)

Caution (Continued)

warranty. Always use the correctautomatic transmission fluid. SeeRecommended Fluids andLubricants 0 85.

Change the fluid and filter atthe scheduled maintenanceintervals listed in MaintenanceSchedule 0 81. Be sure to use thetransmission fluid listed inRecommended Fluids andLubricants 0 85.

Engine Air Filter LifeSystemIf equipped, this feature providesthe engine air filter’s remaining lifeand best timing for a change. Thetiming to change an engine air filterdepends on driving andenvironmental conditions.


Vehicle Care 67

When to Change the EngineAir Filter

When the Driver Information Center(DIC) displays a message to replacethe engine air filter at the next oilchange, follow this timing.

When the DIC displays a messageto replace the engine air filter soon,replace the engine air filter at theearliest convenience.

The system must be reset after theengine air filter is changed.

If the DIC displays a message tocheck the engine air filter system,see your dealer.

How to Reset the Engine AirFilter Life System

To reset:

1. Place the vehicle in P (Park).

2. Display the Air Filter Life on theDIC. See Driver InformationCenter (DIC) 0 12 in theowner’s manual.

3. Press T on the steering wheel,or press the trip odometer resetstem if the vehicle does nothave DIC controls, to move tothe Reset/Disable display area.Select Reset, then press thethumbwheel or press the resetstem for several seconds.

4. Press the thumbwheel or thereset stem to confirm the reset.

Engine Air Cleaner/FilterThe engine air cleaner/filter is in theengine compartment. See EngineCompartment Overview 0 62.

When to Inspect the Engine AirCleaner/Filter

If the vehicle is not equipped withthe engine air filter life system, seeMaintenance Schedule 0 81 forintervals on inspecting andreplacing the engine air cleaner/filter.

How to Inspect/Replace theEngine Air Cleaner/Filter

Do not start the engine or have theengine running with the engine airfilter housing open. Before removingthe engine air filter, make sure thatthe engine air filter housing andnearby components are free of dirtand debris. Remove the engine airfilter. Lightly tap and shake theengine air filter (away from thevehicle) to release dust and dirt.Inspect the engine air filter fordamage, and replace if damaged.Do not clean the engine air filter orcomponents with water orcompressed air. When changing theair filter, remove the dust valve fromthe front intake air duct and cleanout any debris if necessary.

Caution

Water sprayed into or on the airintake box in the enginecompartment may damage the airfilter or electrical components. Donot spray water into or on the airintake box.


68 Vehicle Care

1. Screws (6)2. Housing Cover3. Electrical Connector4. Clamps

To inspect and replace the filter:

1. Disconnect the wiring harnesselectrical connector (3) fromthe air cleaner/filter housingcover (2).

2. Loosen the screws on theclamps (4) holding the air outletduct in place. Do not removethe clamps. Move the air ductaside.

3. Remove the six screws (1)from the housing cover (2).

4. Raise the housing cover. Takecare not to move the aircleaner/filter housing base, toavoid any air leaks.

5. Remove the air cleaner/filterfrom the housing base. Takecare to dislodge as little dirt aspossible.

6. Turn the dust valvecounterclockwise to removefrom the front intake air duct.Check it for debris and cleanout if necessary.

7. Turn the dust valve clockwiseto reinstall.

8. Clean the air cleaner/filtersealing surface and thehousing base.

9. Install the engine air cleaner/filter.

10. Lower the air cleaner/filterhousing cover and secure withthe six screws.

11. Move the air duct in place andtighten the two clamp screws.

12. Reinstall the wiring harnesselectrical connector.

13. If equipped, reset the engineair filter life system afterreplacing the engine air filter.See Engine Air Filter LifeSystem 0 66.

{ Warning

Operating the engine with the aircleaner/filter off can cause you orothers to be burned. Use caution

(Continued)


Vehicle Care 69

Warning (Continued)

when working on the engine. Donot start the engine or drive thevehicle with the air cleaner/filteroff, as flames may be present ifthe engine backfires.

Caution

If the air cleaner/filter is off, dirtcan easily get into the engine,which could damage it. Alwayshave the air cleaner/filter in placewhen driving.

Cooling System (Engine)The cooling system allows theengine to maintain the correctworking temperature.

1. Engine Cooling Fan (Outof View)

2. Low Temperature CoolingCircuit Coolant Surge Tankand Pressure Cap


{ Warning

Do not touch heater or radiatorhoses, or other engine parts.They can be very hot and canburn you. Do not run the engine ifthere is a leak; all coolant could

(Continued)

Warning (Continued)

leak out. That could cause anengine fire and can burn you. Fixany leak before driving thevehicle.

Engine Coolant

The cooling system in the vehicle isfilled with DEX-COOL enginecoolant mixture. See RecommendedFluids and Lubricants 0 85 andMaintenance Schedule 0 81.

The following explains the coolingsystem and how to add coolantwhen it is low. If there is a problemwith engine overheating, see EngineOverheating 0 74.

A 50/50 mixture of clean, drinkablewater and DEX-COOL coolant will:

. Give freezing protection down to−37 °C (−34 °F).

. Give boiling protection up to129 °C (265 °F).

. Protect against rust andcorrosion.


70 Vehicle Care. Help keep the proper engine

temperature.

. Let the warning lights andgauges work as they should.

What to Use

{ Warning

Plain water, or other liquids suchas alcohol, can boil before theproper coolant mixture will. Withplain water or the wrong mixture,the engine could get too hot butthere would not be an overheatwarning. The engine could catchfire and you or others could beburned.

Use a 50/50 mixture of clean,drinkable water and DEX-COOLcoolant which will not damagealuminum parts. If using thismixture, nothing else needs to beadded.

If coolant has to be added morethan four times a year, have yourdealer check the vehicle coolingsystem.

Caution

Do not use anything other than amix of DEX-COOL coolant thatmeets GM StandardGMW3420 and clean, drinkablewater. Anything else can causedamage to the engine coolingsystem and the vehicle, whichwould not be covered by thevehicle warranty.

Never dispose of engine coolant byputting it in the trash, or by pouringit on the ground or into sewers,streams, or bodies of water. Havethe coolant changed by anauthorized service center, familiarwith legal requirements regardingused coolant disposal. This will helpprotect the environment and yourhealth.

Checking Coolant

The coolant surge tank (2) is in theengine compartment on the driverside of the vehicle. See EngineCompartment Overview 0 62 forlocation.

The vehicle must be on a levelsurface. When the engine is cold,the coolant level should be at theindicated mark.


Vehicle Care 71

Adding Coolant

Caution

If coolant is changed or added,always add enough to fill thesystem completely or enginedamage may occur.

If more coolant is needed, add theproper DEX-COOL coolant mixtureat the surge tank, but be careful notto spill it.

{ Warning

Spilling coolant on hot engineparts can burn you. Coolantcontains ethylene glycol and it willburn if the engine parts are hotenough.

{ Warning

Steam and scalding liquids from ahot cooling system are underpressure. Turning the pressurecap, even a little, can cause themto come out at high speed andyou could be burned. Never turnthe cap when the cooling system,including the pressure cap, is hot.Wait for the cooling system andpressure cap to cool.

If no coolant is visible in the surgetank, add coolant as follows:

1. Remove the coolant surge tankpressure cap when the coolingsystem, including the coolantsurge tank pressure cap andupper radiator hose, is nolonger hot.

Turn the pressure cap slowlycounterclockwise aboutone-half turn. If a hiss is heard,wait for that to stop. A hissmeans there is still somepressure left.

2. Keep turning the pressure capslowly, and remove it.

3. Slowly fill the coolant surgetank (2). Do not let the coolantlevel go above the indicatedmark in the tank until after theengine comes to operatingtemperature in Step 4.


72 Vehicle Care

4. With the coolant surge tankpressure cap off, start theengine and let it run until theengine coolant temperaturegauge indicates approximately90 °C (195 °F).

By this time, the coolant levelinside the coolant surge tankmay be lower. If the level islower, slowly add more of theproper mixture to the coolantsurge tank until it reaches theindicated mark.

5. Replace the pressure cap.

Be sure the pressure cap islocked.

6. Verify coolant level after theengine is shut off and thecoolant is cold. If necessary,repeat coolant fill procedureSteps 1–6.

If the coolant level is still low afterhaving followed these steps twice,have the coolant system checked bya certified technician at the dealerfor a possible leak.

Caution

If the pressure cap is not tightlyinstalled, coolant loss and enginedamage may occur. Be sure thecap is properly and tightlysecured.

Cooling System (LowTemperature CoolingCircuit)The cooling system allows thediesel fuel and diesel emission fluidinjector to maintain the correctworking temperature.

1. Engine Cooling Fan (Outof View)

2. Low Temperature CoolingCircuit Coolant Surge Tankand Pressure Cap


{ Warning

Do not touch heater or radiatorhoses, or other engine parts.They can be very hot and canburn you. Do not run the engine ifthere is a leak; all coolant could

(Continued)


Vehicle Care 73

Warning (Continued)

leak out. That could cause anengine fire and can burn you. Fixany leak before driving thevehicle.

Low Temperature CoolingCircuit Coolant

The low temperature cooling circuitcooling system in the vehicle is filledwith DEX-COOL engine coolantmixture. See Recommended Fluidsand Lubricants 0 85 andMaintenance Schedule 0 81.

The following explains the coolingsystem and how to add coolantwhen it is low. If there is a problemwith engine overheating, see EngineOverheating 0 74.

A 50/50 mixture of clean, drinkablewater and DEX-COOL coolant will:

. Give freezing protection down to−37 °C (−34 °F).

. Give boiling protection up to129 °C (265 °F).

. Protect against rust andcorrosion.

. Help keep the proper enginetemperature.

. Let the warning lights andgauges work as they should.

What to Use

{ Warning

Plain water, or other liquids suchas alcohol, can boil before theproper coolant mixture will. Withplain water or the wrong mixture,the engine could get too hot butthere would not be an overheatwarning. The engine could catchfire and you or others could beburned.

Use a 50/50 mixture of clean,drinkable water and DEX-COOLcoolant which will not damagealuminum parts. If using thismixture, nothing else needs to beadded.

If coolant has to be added morethan four times a year, have yourdealer check the vehicle charge aircooling system.

Caution

Do not use anything other than amix of DEX-COOL coolant thatmeets GM StandardGMW3420 and clean, drinkablewater. Anything else can causedamage to the engine coolingsystem and the vehicle, whichwould not be covered by thevehicle warranty.

Never dispose of engine coolant byputting it in the trash, or by pouringit on the ground or into sewers,streams, or bodies of water. Havethe coolant changed by anauthorized service center, familiarwith legal requirements regardingused coolant disposal. This will helpprotect the environment and yourhealth.


74 Vehicle Care

Checking Coolant

The low temperature cooling circuitcoolant surge tank (1) is in theengine compartment on the driverside of the vehicle. See EngineCompartment Overview 0 62 forlocation.

The vehicle must be on a levelsurface. When the engine is cold,the coolant level should be at theindicated mark.

Adding Coolant

If the coolant level in the lowtemperature cooling circuit coolantsurge tank is low, see your dealer to

have the system checked for leaksand purged of air, and the coolantlevel adjusted.

Engine OverheatingThere is an engine coolanttemperature gauge on theinstrument cluster. See the owner’smanual.

If Steam Is Coming from theEngine Compartment

{ Warning

Steam and scalding liquids from ahot cooling system are underpressure. Turning the pressurecap, even a little, can cause themto come out at high speed andyou could be burned. Never turnthe cap when the cooling system,including the pressure cap, is hot.Wait for the cooling system andpressure cap to cool.

Caution

Do not run the engine if there is aleak in the engine cooling system.This can cause a loss of allcoolant and can damage thesystem and vehicle. Have anyleaks fixed right away.

If No Steam Is Coming fromthe Engine Compartment

A Driver Information Center (DIC)message, along with a low coolantcondition, can indicate a seriousproblem.

If there is an engine overheatwarning and the vehicle does nothave a low coolant condition, andno steam is heard or seen, theproblem may not be too serious.Sometimes the engine can get alittle too hot when the vehicle:

. Climbs a long hill on a hot day.

. Stops after high-speed driving.

. Idles for long periods in traffic.


Vehicle Care 75. Tows a trailer. See “Driving on

Grades” under “DrivingCharacteristics and Towing Tips”in the owner’s manual.

If the DIC message comes on withno sign of steam, try this for aminute or so:

1. In heavy traffic, let the engineidle in N (Neutral) whilestopped. If it is safe to do so,pull off the road, shift toP (Park) or N (Neutral), and letthe engine idle.

2. Turn on the heater to full hot atthe highest fan speed andopen the window as necessary.

If the vehicle no longer has theoverheat warning, the vehicle canbe driven. Just to be safe, driveslower for about 10 minutes. If thewarning does not come back on,drive normally and have the coolingsystem checked for proper fill andfunction.

If the warning continues, pull over,stop, and park the vehicleright away.

If there is still no sign of steam andthe vehicle is equipped with anengine driven cooling fan, pushdown the accelerator until theengine speed is about twice as fastas normal idle speed for at leastfive minutes while the vehicle isparked. If the warning is still there,turn off the engine and get everyoneout of the vehicle until it cools down.

If the Action Required - Idle VehicleTo Cool Engine DIC messagedisplays, do not turn the engine off.Keep the engine running until themessage goes away.

Intended Vehicle Use: After aHeavy Towing Event

If equipped, when the vehicle isturned off after towing heavy loads,the system may automaticallyrestart the engine. A chime willsound and DIC messages willdisplay. The engine willautomatically turn off after 10–15 minutes of run time or if enoughcooling has occurred.

If the DIC messages display afterthe vehicle has been stopped andplaced in P (Park) with the enginestill running, remain in the vehiclewith the engine running until thesemessages no longer display. It maytake up to 15 minutes of idling. Donot park the vehicle in an enclosedarea if the messages display.

If the system determines that theengine should be restarted and theignition is turned off, the engine willturn off and then automaticallyrestart. If the engine is restarted,DIC messages display and chimeswill sound. The vehicle cannot beshifted out of P (Park) unless thefeature is overridden.

Never leave occupants in thevehicle, and always take the keysand lock the doors if you must leavethe vehicle idling. Some local lawsprohibit a vehicle from idlingunattended. Always remain with thevehicle until it automatically turnsoff. This could take up to15 minutes.


76 Vehicle Care

If the system determines that thevehicle was not allowed to restart,or if a condition such as an openhood has been detected, then DICmessages display and a chime willsound. To help with systemperformance, either restart theengine, or if the engine is notrunning and the hood can be safelyopened after one minute, open thehood to allow cooling.

If the system has automaticallyrestarted the engine, the vehiclecannot move until cooling hascompleted and the engineautomatically turns off. Overridingthis feature will allow normal vehicleoperation. To override, start thevehicle as you would normally. Theneither drive the vehicle as normal orturn off the ignition if you must exitthe vehicle. Opening the hood willprevent the restart or will turn theengine off when this feature isactive.

Interactions with ManualRegen

If the system has determined thatthe engine should be restarted, thenthe manual regen feature will not beallowed.

If manual regen has been enabled,and the system has determined thatthe engine should be restarted,there will be no chime or DICmessages related to the DieselEngine After Run Feature until themanual regen completes. If theengine is turned off during themanual regen, a restart may occurwithout any alerts.

Engine FanThe vehicle has a clutched enginecooling fan. When the clutch isengaged, the fan spins faster toprovide more air to cool the engine.

In most everyday driving conditions,the fan is spinning slower and theclutch is not fully engaged. Thisimproves fuel economy and reducesfan noise. Under heavy vehicleloading, trailer towing, and/or highoutside temperatures, the fan speedincreases as the clutch more fullyengages, so an increase in fannoise may be heard. This is normaland should not be mistaken as thetransmission slipping or makingextra shifts. It is merely the coolingsystem functioning properly. The fanwill slow down when additionalcooling is not required and theclutch partially disengages.

This fan noise may be heard whenstarting the engine. It will go awayas the fan clutch partiallydisengages.


Vehicle Care 77

Electrical System

Engine CompartmentFuse BlockFor additional fuse and electricalinformation, see “Electrical System”in the owner’s manual.

The Auxilary fuse block is in theengine compartment, on the driverside of the vehicle.

Lift the cover to access the fuseblock.

Caution

Spilling liquid on any electricalcomponent on the vehicle maydamage it. Always keep thecovers on any electricalcomponent.

A fuse puller is available in the leftinstrument panel end cap.

The vehicle may not be equippedwith all the fuses, relays, andfeatures shown.

{ Danger

Fuses and circuit breakers aremarked with their ampere rating.Do not exceed thespecified amperage rating whenreplacing fuses and circuitbreakers. Use of an oversizedfuse or circuit breaker can resultin a vehicle fire. You and otherscould be seriously injured orkilled.

Auxiliary Fuse Block

Fuses Usage

7 Powertrain sensor

8 —

9 Diesel exhaust fluidcontrol

10 Fuel heater

11 Smart sensors

12 SCRPM

13 100 watt pump/—


78 Vehicle Care

Relays Usage

1 Diesel exhaust fluidcontrol

2 Fuel heater

3 100 wattpump (LD)

4 Powertrainsensor (LD)

5 Cooling fanclutch (HD)

6 Powertrainsensor (HD)

Appearance Care

Exterior CareSee the owner’s manual foradditional exterior care information.

Caution

Water sprayed into or on the airintake box in the enginecompartment may damage the airfilter or electrical components. Donot spray water into or on the airintake box.


Service and Maintenance 79

Service andMaintenance

General InformationGeneral Information . . . . . . . . . . . . 79

Maintenance ScheduleMaintenance Schedule . . . . . . . . 81

Recommended Fluids,Lubricants, and PartsRecommended Fluids andLubricants . . . . . . . . . . . . . . . . . . . . 85

Maintenance ReplacementParts . . . . . . . . . . . . . . . . . . . . . . . . . 86

Maintenance RecordsMaintenance Records . . . . . . . . . 87

General InformationThis maintenance section applies tovehicles with a diesel engine. Forgasoline engine vehicles, see themaintenance schedule section inthe owner’s manual.

Your vehicle is an importantinvestment. This section describesthe required maintenance for thevehicle. Follow this schedule to helpprotect against major repairexpenses resulting from neglect orinadequate maintenance. It mayalso help to maintain the value ofthe vehicle if it is sold. It is theresponsibility of the owner to haveall required maintenance performed.

Your dealer has trained technicianswho can perform requiredmaintenance using genuinereplacement parts. They haveup-to-date tools and equipment forfast and accurate diagnostics. Manydealers have extended evening andSaturday hours, courtesytransportation, and onlinescheduling to assist with serviceneeds.

Your dealer recognizes theimportance of providingcompetitively priced maintenanceand repair services. With trainedtechnicians, your dealer is the placefor routine maintenance such as oilchanges and tire rotations andadditional maintenance items liketires, brakes, batteries, and wiperblades.

Caution

Damage caused by impropermaintenance can lead to costlyrepairs and may not be coveredby the vehicle warranty.Maintenance intervals, checks,inspections, recommended fluids,and lubricants are important tokeep the vehicle in good workingcondition.

Do not have chemical flushes thatare not approved by GMperformed on the vehicle. Theuse of flushes, solvents, cleaners,or lubricants that are not

(Continued)


80 Service and Maintenance

Caution (Continued)

approved by GM could damagethe vehicle, requiring expensiverepairs that are not covered bythe vehicle warranty.

The Tire Rotation and RequiredServices are the responsibility of thevehicle owner. It is recommended tohave your dealer perform theseservices every 12 000 km/7,500 mi.Proper vehicle maintenance helps tokeep the vehicle in good workingcondition, improves fuel economy,and reduces vehicle emissions.

Because of the way people usevehicles, maintenance needs vary.There may need to be morefrequent checks and services. TheAdditional Required Services -Normal are for vehicles that:

. Carry passengers and cargowithin recommended limits onthe Tire and Loading Informationlabel. See “Vehicle Load Limits”in the owner’s manual.

. Are driven on reasonable roadsurfaces within legal drivinglimits.

. Use the recommended fuel. SeeFuel for Diesel Engines 0 30.

Refer to the information in theMaintenance Schedule AdditionalRequired Services - Normal chart.

The Additional Required Services -Severe are for vehicles that are:

. Mainly driven in heavy city trafficin hot weather.

. Mainly driven in hilly ormountainous terrain.

. Frequently towing a trailer.

. Used for high speed orcompetitive driving.

. Used for taxi, police, or deliveryservice.

Refer to the information in theMaintenance Schedule AdditionalRequired Services - Severe chart.

{ Warning

Performing maintenance work canbe dangerous and can causeserious injury. Performmaintenance work only if therequired information, proper tools,and equipment are available.If they are not, see your dealer tohave a trained technician do thework. See “Doing Your OwnService Work” in the owner’smanual.



MaintenanceScheduleOwner Checks and Services

See the owner’s manual for otherservices and intervals that may berequired.

At Each Fuel Stop

. Check DEF percentage. SeeDiesel Exhaust Fluid 0 25.

. Check the engine oil level. SeeEngine Oil 0 63.

Engine Oil Change

When the CHANGE ENGINE OILSOON message displays, have theengine oil and filter changed withinthe next 1 000 km/600 mi. If drivenunder the best conditions, theengine oil life system may notindicate the need for vehicle servicefor up to a year. The engine oil and

filter must be changed at least oncea year and the oil life system mustbe reset. Your trained dealertechnician can perform this work.If the engine oil life system is resetaccidentally, service the vehiclewithin 5 000 km/3,000 mi since thelast service. Reset the oil lifesystem when the oil is changed.See Engine Oil Life System 0 66.

Engine Air Filter Change

When the REPLACE AT NEXT OILCHANGE message displays, theengine air filter should be replacedat the next engine oil change. Whenthe REPLACE ENGINE AIR FILTERSOON message displays, theengine air filter should be replacedat the earliest convenience. Resetthe engine air filter life system afterthe engine air filter is replaced. SeeEngine Air Filter Life System 0 66.

Power Take Off (PTO) andExtended Idle Use

When the vehicle is used with thePTO equipment or used in a waythat requires extended idle time,one hour of use shall be deemedthe same as 53 km (33 mi). SeeDriver Information Center (DIC) forhourmeter, if equipped.

Required Services Every12 000 km/7,500 mi. Check engine oil level and oil

life percentage. If needed,change engine oil and filter, andreset oil life system.See Engine Oil 0 63 andEngine Oil Life System 0 66.


82 Service and Maintenance. If equipped with the engine air

filter life system, check the airfilter life percentage.If necessary, replace the engineair filter and reset the engine airfilter life system. See Engine AirFilter Life System 0 66. If thevehicle is not equipped with theengine air filter life system,inspect the engine air cleanerfilter. See Engine Air Cleaner/Filter 0 67.

. Check engine coolant level. SeeCooling System (Engine) 0 69 orCooling System (LowTemperature Cooling Circuit)0 72.

. Visually check for fluid leaks.

. Visually inspect fuel system fordamage or leaks.

. Visually inspect exhaust systemand nearby heat shields forloose or damaged parts.



Maintenance ScheduleAdditional RequiredServices - Normal

12000km/7,500mi

24000km/15,000mi

36000km/22,500mi

48000km/30,000mi

60000km/37,500mi

72000km/45,000mi

84000km/52,500mi

96000km/60,000mi

108000km/67,500mi

120000km/75,000mi

132000km/82,500mi

144000km/90,000mi

156000km/97,500mi

168000km/105,000mi

180000km/112,500mi

192000km/120,000mi

204000km/127,500mi

216000km/135,000mi

228000km/142,500mi

240000km/150,000mi

Perform Required Services. Check engine oillevel and oil life percentage. Change engine oiland filter, if needed. Check engine air filter life per-centage and status. Change engine air filter,if needed

@ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @

If the vehicle is not equipped with the engine airfilter life system, replace engine air cleanerfilter. (1)

@ @ @

Drain and fill engine cooling system. (2) @

Visually inspect accessory drive belts. (3) @

Replace fuel filter. (4) @ @ @ @ @ @

Footnotes — MaintenanceSchedule Additional RequiredServices - Normal

(1) Or every four years, whichevercomes first. If driving in dustyconditions, inspect the filter at eachoil change or more often as needed.See Engine Air Cleaner/Filter 0 67.

(2) Or every five years, whichevercomes first. See Cooling System(Engine) 0 69 orCooling System (Low TemperatureCooling Circuit) 0 72.

(3) Or every 10 years, whichevercomes first. Inspect for fraying,excessive cracking, or damage;replace, if needed.

(4) Or every two years, or when theCHANGE FUEL FILTER message inthe Driver Information Center (DIC)comes on, whichever comes first.The fuel filter may need to bereplaced more often based onbiodiesel usage, driving in climateswith severe dust, off-road driving,or towing a trailer for extendedperiods.



Maintenance ScheduleAdditional RequiredServices - Severe

12000km/7,500mi

24000km/15,000mi

36000km/22,500mi

48000km/30,000mi

60000km/37,500mi

72000km/45,000mi

84000km/52,500mi

96000km/60,000mi

108000km/67,500mi

120000km/75,000mi

132000km/82,500mi

144000km/90,000mi

156000km/97,500mi

168000km/105,000mi

180000km/112,500mi

192000km/120,000mi

204000km/127,500mi

216000km/135,000mi

228000km/142,500mi

240000km/150,000mi

Perform Required Services. Check engine oillevel and oil life percentage. Change engine oiland filter, if needed. Check engine air filter life per-centage and status. Change engine air filter,if needed.

@ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @ @

If the vehicle is not equipped with the engine airfilter life system, replace engine air cleanerfilter. (1)

@ @ @

Change automatic transmission fluid and filter. @ @ @

Drain and fill engine cooling system. (2) @

Visually inspect accessory drive belts. (3) @

Replace fuel filter. (4) @ @ @ @ @ @

Footnotes — MaintenanceSchedule Additional RequiredServices - Severe

(1) Or every four years, whichevercomes first. If driving in dustyconditions, inspect the filter at eachoil change or more often as needed.See Engine Air Cleaner/Filter 0 67.

(2) Or every five years, whichevercomes first. See Cooling System(Engine) 0 69 orCooling System (Low TemperatureCooling Circuit) 0 72.

(3) Or every 10 years, whichevercomes first. Inspect for fraying,excessive cracking, or damage;replace, if needed.

(4) Or every two years, or when theCHANGE FUEL FILTER message inthe Driver Information Center (DIC)comes on, whichever comes first.The fuel filter may need to bereplaced more often based onbiodiesel usage, when driving inclimates with excessive dust,or when off-road driving or towing atrailer for extended periods.



Recommended Fluids, Lubricants, and Parts

Recommended Fluids and LubricantsThe following fluids apply to vehicles with a Duramax diesel engine. For other fluids not listed here, see“Recommended Fluids and Lubricants” in the owner’s manual.

Fluids and lubricants identified below by name, part number, or specification can be obtained from your dealer.

Usage Fluid/Lubricant

Automatic Transmission DEXRON ULV Automatic Transmission Fluid (GM Part No. 19352619, inCanada 19352620).

Diesel Exhaust AftertreatmentSystem

Diesel Exhaust Fluid (GM Part No. 19286291, in Canada 88862660) orDiesel Exhaust Fluid that meets ISO 22241 or displays the API DieselExhaust Fluid Certification Mark.

Engine Coolant 50/50 mixture of clean, drinkable water and use only DEX-COOL coolant.See Cooling System (Engine) 0 69 orCooling System (Low Temperature Cooling Circuit) 0 72.

Engine Oil Engine oils with the letters CJ-4 or CK-4 are required for your vehicle. TheCJ-4 or CK-4 designation can appear either alone or in combination withother American Petroleum Institute (API) designations, such as API CJ-4/SL. These letters show API levels of quality. To determine the preferredviscosity for your vehicle's diesel engine, see Engine Oil 0 63.

Hydraulic Power Steering System GM Power Steering Fluid (GM Part No. 19329450, in Canada 19329451).



Maintenance Replacement PartsReplacement parts identified below by name, part number, or specification can be obtained from your dealer.

Part GM Part Number ACDelco Part Number

Engine Air Cleaner/Filter 84554703 A3248C

Fuel Filter 23304096 TP1015

Engine Oil Filter 12684038 PF26

Use only the specified filters.



Maintenance RecordsAfter the scheduled services are performed, record the date, odometer reading, who performed the service, and thetype of services performed in the boxes provided. Retain all maintenance receipts.

DateOdometerReading

Serviced By Services Performed


88 Technical Data

Technical Data

Vehicle DataCapacities andSpecifications . . . . . . . . . . . . . . . . 89

Engine Drive Belt Routing . . . . . 91


Technical Data 89

Vehicle Data

Capacities and SpecificationsThe following approximate capacities are given in metric and English conversions. See Recommended Fluids andLubricants 0 85.

Application

Capacities

Metric English

Engine Cooling System* 29.1 L 30.7 qt

Low Temperature Cooling Circuit Cooling System* 3.5 L 3.7 qt

Diesel Exhaust Fluid (DEF) Tank** 26.5 L 7.0 gal

Engine Oil with Filter 9.5 L 10.0 qt

Transfer Case Fluid

1500 Series 1.5 L 1.6 qt

2500 Series and 3500 Series 2.3 L 2.4 qt

Hydraulic Power Steering Fluid 2.0 L 2.1 qt

*Engine cooling system capacity values are based on the entire cooling system and its components.

**Do not overfill the DEF tank. See Diesel Exhaust Fluid 0 25.

All quantities are approximate. When adding, be sure to fill to the appropriate level, as recommended in thismanual. Recheck fluid level after filling.


90 Technical Data

Engine Specifications

Engine VIN Code Type

6.6L 8-Cylinder Turbo Diesel (L5P Engine) Y V8


Technical Data 91

Engine Drive Belt Routing

6.6L 8-Cylinder Engine (SingleGenerator)

6.6L 8-Cylinder Engine (DualGenerator)

Fan Drive Belt Routing(Secondary/Auxiliary Drive)


92 Index

Index AAccessories and Modifications . . . 60Air Cleaner/Filter, Engine . . . . . . . . 67Air FilterLife System . . . . . . . . . . . . . . . . . . . . .66

Appearance CareExterior . . . . . . . . . . . . . . . . . . . . . . . . .78

AutomaticTransmission Fluid . . . . . . . . . . . . .66

BBiodiesel . . . . . . . . . . . . . . . . . . . . . . . . 31BrakeExhaust . . . . . . . . . . . . . . . . . . . . . . . .29

CCanadian Vehicle Owners . . . . . . . . 2Capacities and Specifications . . . . 89CheckEngine Light (MalfunctionIndicator) . . . . . . . . . . . . . . . . . . . . . .10

CleaningExterior Care . . . . . . . . . . . . . . . . . . .78

Cluster, Instrument . . . . . . . . . . . . . . . 6Cold Weather Operation . . . . . . . . . 32Cooling System . . . . . . . . . . . . . . 69, 72CoversWinter . . . . . . . . . . . . . . . . . . . . . . . . . .18

DDieselStarting Your Engine . . . . . . . . . . . .15

Diesel Exhaust Fluid . . . . . . . . . . . . . 25Diesel Exhaust Fluid (DEF)Warning Light . . . . . . . . . . . . . . . . . . 11

Diesel Particulate Filter . . . . . . . . . . 22Drive Belt Routing, Engine . . . . . . . 91Driver InformationCenter (DIC) . . . . . . . . . . . . . . . . . . . 12

EElectrical SystemEngine Compartment FuseBlock . . . . . . . . . . . . . . . . . . . . . . . . . .77

EngineAir Cleaner/Filter . . . . . . . . . . . . . . .67Check Light (MalfunctionIndicator) . . . . . . . . . . . . . . . . . . . . . .10

Compartment Overview . . . . . . . . .62Cooling System . . . . . . . . . . . . . 69, 72Drive Belt Routing . . . . . . . . . . . . . .91Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . .76Heater . . . . . . . . . . . . . . . . . . . . . . . . . .21Oil Life System . . . . . . . . . . . . . . . . .66Overheating . . . . . . . . . . . . . . . . . . . .74Starting Your Diesel . . . . . . . . . . . .15

Engine Air Filter Life System . . . . . 66


Index 93

EnginesDiesel Fuel . . . . . . . . . . . . . . . . . . . . .30

Exhaust Brake . . . . . . . . . . . . . . . . . . . 29Exhaust FluidDiesel . . . . . . . . . . . . . . . . . . . . . . . . . .25

FFanEngine . . . . . . . . . . . . . . . . . . . . . . . . . .76

Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Replacement (Fuel) . . . . . . . . . . . . .36

Filter,Engine Air Cleaner . . . . . . . . . . . . .67

FluidAutomatic Transmission . . . . . . . .66

FuelAdditives . . . . . . . . . . . . . . . . . . . . . . .30Biodiesel . . . . . . . . . . . . . . . . . . . . . . .31Cold Weather Operation . . . . . . . .32Diesel Engines . . . . . . . . . . . . . . . . .30Filling a Portable FuelContainer . . . . . . . . . . . . . . . . . . . . .39

Filling the Tank . . . . . . . . . . . . . . . . .37Filter Replacement . . . . . . . . . . . . .36Running out of Fuel . . . . . . . . . . . . .36Top Tier . . . . . . . . . . . . . . . . . . . . . . . .30Water in Fuel . . . . . . . . . . . . . . . . . . .33

Fuel for Diesel Engines . . . . . . . . . . 30

FusesEngine Compartment FuseBlock . . . . . . . . . . . . . . . . . . . . . . . . . .77

GGeneral InformationService and Maintenance . . . . . . .79

HHeaterEngine . . . . . . . . . . . . . . . . . . . . . . . . . .21

IInstrument Cluster . . . . . . . . . . . . . . . . 6Introduction . . . . . . . . . . . . . . . . . . . . . . . 2

LLampsMalfunction Indicator (CheckEngine) . . . . . . . . . . . . . . . . . . . . . . .10

LightsCheck Engine (MalfunctionIndicator) . . . . . . . . . . . . . . . . . . . . . .10

Diesel Exhaust Fluid (DEF) . . . . . 11Power Take-off . . . . . . . . . . . . . . . . .12Wait to Start . . . . . . . . . . . . . . . . . . . . 11

MMaintenanceRecords . . . . . . . . . . . . . . . . . . . . . . . .87

Maintenance Schedule . . . . . . . . . . 81

Maintenance Schedule (cont'd)Recommended Fluids andLubricants . . . . . . . . . . . . . . . . . . . . .85

Malfunction Indicator Lamp . . . . . . 10

OOilEngine . . . . . . . . . . . . . . . . . . . . . . . . . .63Engine Oil Life System . . . . . . . . .66

Overheating, Engine . . . . . . . . . . . . . 74

PParkingOver Things That Burn . . . . . . . . .22

PersonalizationVehicle . . . . . . . . . . . . . . . . . . . . . . . . .13

Power Take-Off (PTO) . . . . . . . . . . . 41Power Take-Off Light . . . . . . . . . . . . 12

RRecommended Fluids andLubricants . . . . . . . . . . . . . . . . . . . . . . 85

RecordsMaintenance . . . . . . . . . . . . . . . . . . . .87

Replacement PartsMaintenance . . . . . . . . . . . . . . . . . . . .86

Routing, Engine Drive Belt . . . . . . . 91Running out of Fuel . . . . . . . . . . . . . . 36


94 Index

SServiceAccessories andModifications . . . . . . . . . . . . . . . . . .60

Maintenance Records . . . . . . . . . .87Maintenance, GeneralInformation . . . . . . . . . . . . . . . . . . . .79

Specifications and Capacities . . . . 89Starting the Diesel Engine . . . . . . . 15SupplementUsing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

SystemEngine Air Filter Life . . . . . . . . . . . .66

TTop Tier Fuel . . . . . . . . . . . . . . . . . . . . 30TowingTrailer . . . . . . . . . . . . . . . . . . . . . . . . . .39

TrailerTowing . . . . . . . . . . . . . . . . . . . . . . . . . .39

TransmissionFluid, Automatic . . . . . . . . . . . . . . . .66

UUsing This Supplement . . . . . . . . . . . 2

VVehicleCanadian Owners . . . . . . . . . . . . . . . 2

Vehicle (cont'd)Personalization . . . . . . . . . . . . . . . . .13

WWait to Start Light . . . . . . . . . . . . . . . 11Water in Fuel . . . . . . . . . . . . . . . . . . . . 33Winter Cover . . . . . . . . . . . . . . . . . . . . 18

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