troublshooting g3608.pdf

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Welcome: m400mwz

Product: GAS ENGINE

Model: G3608 GAS ENGINE 4WF00168

Configuration: G3608 GENERATOR AND INDUSTRIAL 4WF00001-UP

Troubleshooting G3600 ENGINES Media Number -SENR6510-05 Publication Date -01/01/2002 Date Updated -13/05/2011

SENR65100007

Section 4: Systems Functional Tests

How To Use Tests

Systems Operation

This area is used to describe subsystem component operation and other pertinent details for

troubleshooting.

Control or Sensor Signals

The input and/or output signals are discussed in this area. Generally, each signal is discussed withspecifications.

Control Diagnostics

Any control diagnostics which directly relate to the component are briefly discussed. Engine orcontrol response due to a diagnostic code may also be discussed.

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NOTE: There are two basic wiring arrangements used on G3600 engines. The early engines usedhard conduit on the engine and the engine mounted junction box terminals were labeled from 101to 458. The later engines used individual flexible stainless steel harnesses and the junction boxterminals were labeled from 610 to 958. The later version has been upgraded over time to includethe Caterpillar Ignition System (CIS), Detonation Mixing Control (DMC), and the Hydraxactuators. The harnesses and junction box termination labels have remained essentially the samewith necessary hardware additions and deletions. The schematics in this publication show only thelater version terminal points. For the early versions reference the Electrical Schematics fortermination points.




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Diagnostic Codes

Inspecting Electrical Connectors

Test Procedure 1

Many of the System Troubleshooting Procedures in this manual will recommend checking aspecific electrical connector. The following procedure will assist in the examination of theconnector to determine if it is the cause of the problem. If a problem is found in the electrical




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connector or connection, repair it if possible. If it cannot be repaired, replace the faulty connectoror wiring harness.

DO NOT cut the Deutsch connector wires if the connector must be replaced, The Deutsch Styleconnectors are repairable without the need to cut the wires. New pins and sockets can be insertedwith a crimp tool.

NOTE: Wiggle the wires while the engine is running to reveal any intermittent diagnostic codes.

NOTE: Clean electrical connections with an alcohol based cleaner when any connector isunmated in a dirt environment.

NOTE: Turn the Mode Control Switch (MCS) to the OFF/RESET position and open the fuse breaker in the ESS panel before doing wiring checks or disconnecting any harnesses.

Deutsch Connectors




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Functional Test




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Figure 3: DDT Wiring Schematic




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Diagnostic Codes

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Functional Test




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SCM Speed Sensor

System Operation

The SCM Engine Speed Sensor (MPU) is a passive magnetic pickup sensor that provides enginespeed to the SCM.

The Engine Speed Sensor must be installed with an air gap of one half to three fourthscounterclockwise turn from full bottom position. A properly adjusted air gap will prevent nuisancediagnostics.

NOTE: The sensor is shared with the Timing Control Module (TCM) and DMC where applicable.

The sensor outputs a sinusoidal waveform created as the flywheel ring gear teeth pass beneath the pickup. The frequency of the signal is proportional to the speed of the engine. The signal can be




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interpreted as engine speed (rpm) equals frequency (Hz) multiplied by 60 then divided by thenumber of teeth (255).

rpm=(Hz) X 60 / (255)

The frequency of the signal can be measured using a voltmeter with an AC frequency mode or anoscilloscope.

Figure 2: SCM Speed Sensor Schematic




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Figure 3: Speed Sensor Output Table

Diagnostic Codes




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Functional Test




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Oil Pressure/Temperature Module

System Operation

The SCM monitors the oil pressure and oil temperature to provide basic engine protection.

The Oil Pressure/Temperature Module (or Transducer Module) receives engine oil pressure sensorand oil temperature sensor values and relays the information to the SCM.

The sensor module sends the engine oil temperature and pressure information to the SCM in aserial communications message.

Figure 1: Oil Pressure/Temperature Module Diagram




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Figure 2: Oil Pressure/Temperature Module Schematic

Refer to the Electrical Schematic for the terminations.

Diagnostic Codes




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Functional Test




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Mode Control Switch (MCS)

System Operation

The Status Control Module (SCM) uses the Mode Control Switch (MCS) to control the startingand stopping functions for the engine.

Placing the Mode Control Switch (MCS) to the OFF/RESET position is used to clear and resetdiagnostic fault codes.

The SCM input is connected to ground by the MCS to determine the MCS switch position.

This diagnostic code will be active if there is an open or short from the Mode Control Switch(MCS) to the SCM. At least one input (AUTO, START, STOP or OFF/RESET) must beconnected to -Battery.




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Figure 2: Mode Control Switch Schematic





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Diagnostic Codes




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Functional Test




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SCM Memory/Program Mismatch




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System Operation

The programmable set point information is stored and used in the control strategy of the SCM.The set points programmed into the SCM are factory set. The set points can be changed for anapplication specific configuration or when a special (usually Overcrank or cycle crank) is needed.

Diagnostic Codes




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Functional Test

Engine Shutdown

System Operation

The diagnostic code indicates that the engine was shut down by an external engine relatedcomponent or condition and the SCM did not receive a shutdown command before the enginespeed reached 50 rpm. The most common conditions are described below. Fuel supply is turnedOFF. Airflow to the engine inlet air system is restricted. Ignition system shutdown is active.




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Figure 1: Status Control Module




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Diagnostic Codes




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SCM Voltage Supply




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System Operation

The SCM continuously monitors the system battery voltage. The SCM displays the informationand monitors for insufficient battery voltage.

Figure 1: Status Control Module

Diagnostic Code




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Functional Test




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SCM Temperature Probe

System Operation

The sensor is a resistive type sensor. The Oil Temperature Sensor probe monitors oil temperatureand is used to protect the engine from high oil temperature operation.




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Figure 2: Oil Pressure/Temperature Module Schematic




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Diagnostic Codes

Functional Test

Figure 3: Temperature Sensor Resistance Table




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SCM Oil Pressure Probe

System Operation

The sensor is a resistive type sensor. The Oil Temperature Sensor probe monitors oil temperatureand is used to protect the engine from high oil temperature operation.




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Diagnostic Codes

Functional Test




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Battery Voltage Low

System Operation

The ESS System Panel continuously monitors the System Battery Voltage with the CMS Module.The ECM uses the information to protect the engine from operation with insufficient batteryvoltage. The ECM can be selected (via the Personality Module) to either generate a Shutdown,generate an Alarm, or not monitor the System Battery Voltage at all.

Although this sensor (or data) is read by the CMS Module, the sensor data output is relayed viathe CAT Data Link to the ECM and processed. The ECM performs the diagnostics associated withthis data.

Control Diagnostics




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168-01 (Not Flashing) Battery Voltage Low Alarm indicates the system battery voltage hasdropped below the Low Battery Voltage Alarm Level. Std=20 VDC

168-01 (Flashing) Battery Voltage Low Shutdown Level indicates the battery voltage is at theminimum programmed parameter for a certain period of time. The ECM will display a flashingdiagnostic code and the engine will shut down. Std= 18 VDC

Figure 2: Battery Schematic




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Diagnostic Codes




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Functional Test




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Gas Shutoff Valve (GSOV) Failure

System Operation

The Gas Shutoff Valve is an electrically actuated solenoid valve that controls the fuel supply tothe engine. This valve is used to interrupt the fuel flow to the engine and is the Primary means ofshutting down the engine. The Status Control Module (SCM) uses an internal fuel control relay(FCR) to energize the Gas Shutoff Valve. The gas control valve is energized (opened) by sending+battery to its solenoid. The valve is de-energized (closed) by open circuiting the solenoid.

Control Diagnostics

017-12 Gas Shutoff Valve Failure

Once the shutdown has been initiated (the Gas Shutoff Valve should now be closed) the ECMmomentarily opens the fuel control valve when Fuel Manifold pressure drops to 1 kPa. If the fuel

pressure exceeds 30.0 kPa (4.35 psi) the fuel control valve is open, the ECM generates the 017-12Diagnostic Fault Code.

Figure 1: Gas Shutoff Valve Diagram




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Figure 2: Gas Shutoff Valve Schematic




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Diagnostic Codes

Functional Test




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Fuel Temperature Sensor

System Operation

The Fuel Temperature Sensor provides the temperature of the fuel in the fuel manifold to the

Engine Control Module (ECM). The ECM monitors the fuel temperature as an essential part of air -to-fuel ratio control. The sensor provides a DC voltage signal corresponding to the fueltemperature.




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Sensor Supply

The sensor is powered from the 10 VDC Supply from the ECM.

Output Signal

The sensor outputs a DC voltage signal to the ECM. The DC voltage level varies with measured

temperature. The valid voltage range is from 0.6 VDC to 5.1 VDC.

Control Diagnostics

521-00 (Not Flashing) Fuel Temperature Alarm Level indicates the fuel temperature exceeded80°C (176°F). The ECM will display a constant diagnostic code.

521-12 (Not Flashing) Fuel Temperature Sensor Failure indicates the Fuel Temperature Sensorhas provided data outside the range expected from a properly functioning sensor.

Figure 1: Fuel Temperature Sensor Diagram

Figure 2: Fuel Temperature Sensor Schematic





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Figure 3: Fuel Temperature Sensor Output Table

Diagnostic Codes




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Functional Test




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Exhaust Temperature Input

System Operation

The ECM monitors the exhaust stack temperature to protect the engine. In most applications, highexhaust temperature will result in a shutdown, however in some limited applications, high exhausttemperature may be an alarm only. To determine if high exhaust temperature is an alarm or a




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shutdown, check the Personality Module settings for this engine. The Pyrometer Module(s) provide a contact closure when the exhaust temperature rises above the maximum acceptable level(adjustable on the Pyrometer). The switch provides a 0 VDC (-Batt) signal to the ECM byconnecting Switch Input 5 (ECM connector J3 pin-37) to analog ground. When the switch is open,the voltage will be about 14 VDC.

The ECM can be selected (via the Personality Module) to either generate a Shutdown, generate a

Alarm or not monitor the exhaust temperature at all.

Control Diagnostics

535-00 (Not Flashing) Exhaust Temperature Alarm Level indicates the exhaust temperaturehas risen above the maximum allowed level. The ECM will display a constant diagnostic code.

535-00 (Flashing) Exhaust Temperature Shutdown Level indicates the exhaust temperature hasrisen above the maximum allowed level. The ECM will display a flashing diagnostic code and theengine will shut down.

NOTE: The standard setting is 600°C (1110°F) as a shutdown.

Figure 1: Exhaust Temperature Input Diagram




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Figure 2: Exhaust Temperature Input Schematic

Diagnostic Codes




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Functional Test




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Crank Angle Sensor

System Operation

The Crank Angle Sensor (CAS) is a passive magnetic pickup sensor used to indicate crankshaftangle to the Timing Control Module. The Crank Angle Sensor signal indicates cylinder No. 1 TopCenter (TC) on compression and exhaust strokes. The signal is used to control timing andcalculate actual timing and calculate engine rpm.

Output Signal

The sensor outputs a single sinusoidal pulse as the Top Center hole in the flywheel passes beneaththe pickup. One pulse is generated for every crankshaft revolution. The time between pulses is

proportional to the engine speed.

Figure 1: Crank Angle Sensor Diagram




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Figure 2: Crank Angle Sensor Schematic

Figure 3: Crank Angle Sensor Output Table




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Diagnostic Codes




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Functional Test




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Sensor Supply

The sensor is powered from the 10 VDC supply from the ECM. This is shared with several othersensors.

Output Signal

The sensor outputs a DC voltage signal to the ECM. The DC voltage level varies with measuredtemperature. The varied voltage range is from about 0.6 VDC at -40°C (-40°F) to 5.1 VDC at 120°C (248F).

Control Diagnostics

110-00 (Not Flashing) High Jacket Water Temperature Alarm Level indicates the coolantwater temperature exceeds the programmed parameter. The ECM will display a constantdiagnostic code.

110-00 (Flashing) High Jacket Water Temperature Shutdown Level indicates the coolant

water temperature has exceeded the programmed parameter for more than 1 minute. The standardShutdown Point is 98°C (208°F), CoGen and BioGas unit may be different.

110-01 (Not Flashing) Low Jacket Water Temperature Alarm Level indicates the coolantwater temperature does not reach the minimum programmed parameter value. The ECM willdisplay a constant diagnostic code.

NOTE: If the Jacket Water Temperature is below 25°C (77°F) the ECM will display 110-01alarm immediately. If the Jacket Water Temperature is above 25°C (77°F), but below 75°C (167°F) for more than 30 minutes the ECM will then also display the 110-01 Low Water Temp Alarm.

110-12 (Flashing) Jacket Water Temperature Sensor Failure indicates the Jacket Water

Temperature Sensor has provided data outside the range expected from a properly functioningsensor.

Figure 1: Jacket Water Temperature Diagram




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Diagnostic Codes




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Functional Test




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Engine Is Overloaded

System Operation

This input is used to provide an alarm to alert the operator of an engine overload condition and thecontrol can not maintain desired engine rpm.

Figure 1: Engine Is Overloaded Diagram




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Diagnostic Codes

Functional Test




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TCM Flywheel Sensor

System Operation

The Flywheel Sensor is a passive magnetic pickup sensor that provides the engine speed andengine crankshaft position information to the Timing Control Module (TCM). Also used by the

SCM and DMC.

Output Signal

The sensor outputs a sinusoidal wave form created as the flywheel ring gear teeth pass beneath the pickup. The frequency of the signal is proportional to engine seed where 3825 Hz equals 900 rpm.

Frequency/4.25=rpm

Figure 1: Flywheel Sensor Diagram

Figure 2: Flywheel/Crank Angle Sensor Schematic




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Figure 3: Flywheel Sensor Output Table




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Diagnostic Codes




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Funtional Test




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Ignition Timing

System Operation

The Magneto Interface Box (MIB) or the Caterpillar Ignition System (CIS) signal is a reducedvoltage signal of the magneto's odd bank capacitor charge. This signal is sent from the MagnetoIgnition Box (MIB) to the Timing Control. The wave form consists of pulses that indicate the

discharge of the odd bank capacitor to fire the odd cylinders. One pulse is shown for each oddcylinder. This signal is used by the Timing Control to calculate ignition timing and some ignitiondiagnostics.




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Interface Signal

Magneto Interface Ignition Pulse Signal- The waveform consists of pulses that indicate thedischarge of the odd number cylinder banks capacitor to fire the odd numbered cylinders. One

pulse is shown for each odd numbered cylinder.

Control Diagnostics

326-09 (Flashing) No Mag Interface Signal

326-11 (Flashing) Timing Problem Shutdown

The diagnostic codes for this signal are activated by the TCM when no ignition pulses are receivedfrom the MIB. This diagnostic code is only detected on startup while the engine speed is between120 and 300 rpm. If no pulse is detected for 500 ms after engine speed is greater than 120 rpm and

below 300 rpm, the diagnostic is activated. Related diagnostics are from Crank Angle Sensor orTiming/Speed Sensor failures.




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Figure 2: Timing Schematic




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Diagnostic Codes




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Functional Test




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Inlet Manifold Air Temperature Sensor

System Operation

The Inlet Manifold Air Temperature Sensor provides inlet air temperature data to the EngineControl Module (ECM). The ECM uses air temperature in the calculations for airflow and air-to-fuel ratio control. The ECM also uses the sensor to protect the engine against excessively high airtemperatures. The inlet manifold temperature can be read from the CMS (gauge 1) or with theDDT.

Sensor Supply

The sensor is powered from the 10 VDC Supply from the ECM. This voltage supply is sharedwith several other sensors.

Output Signal

The sensor outputs a DC voltage signal to the ECM. The DC voltage level varies with measured temperature. The valid voltage range is from about 0.6 VDC at -40°C (-40°F) to 5.1 VDC at 120°C (248°F).

Control Diagnostics

172-00 (Not Flashing) High Inlet Manifold Air Temperature Alarm

When the load on the engine is below 50 percent of the rated load, the High Air Temp (Load lessthan 50 percent) Alarm Level is used as the Alarm setting.




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When the load on the engine is above 50 percent of the rated load, the High Air Temp (Loadgreater than 50 percent) Alarm Level is used as the Alarm setting.

172-00 ( Flashing) High Inlet Manifold Air Temperature Shutdown

When the load on the engine is below 50 percent of the rated output, the High Air Temp (Loadless than 50 percent) Shutdown Level is used as the Shutdown setting.

When the load on the engine is above 50 percent of the rated load, the High Air Temp (Loadgreater than 50 percent) Shutdown Level is used as the Shutdown setting.

172-12 ( Flashing) Inlet Manifold Air Temperature Sensor Failure

The Inlet Manifold Air Temperature Sensor has provided data outside the normal operating rangeexpected from a properly functioning sensor. The failure is detected at voltages below 0.6 VDC orabove 5.1 VDC.

Figure 1: Inlet Manifold Air Temperature Sensor Diagram

Figure 2: Inlet Manifold Air Temperature Sensor Schematic




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Figure 3: Inlet Manifold Air Temperature Sensor Table




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Diagnostic Codes




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Functional Test




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Personality Module

System Operation

The Personality module contains the software for the ECM that provides all of the features relatedto the ECM. The Personality Module provides a mechanism for changing functions of the control

system. (Factory Programmable Only).

Figure 1: Personality Module Diagram




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Diagnostic Codes




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Functional Test

Coolant Inlet Pressure High

System Operation

The ESS monitors the inlet pressure of the coolant in the engine jacket water system and providesa switch output to the ECM indicating if coolant pressure is above the programmed inlet pressureof the switch. Although the sensor (or data) is read by the CMS module, the switch data output isrelayed via the CAT Data Link to the ECM and processed. The ECM performs the diagnostics




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associated with this switch. The Coolant Inlet Pressure Switch provides an open contact when thecoolant inlet pressure is below the maximum acceptable inlet pressure trip point. If the coolantinlet pressure is above 147 kpa gauge (21 psig), the switch is closed.

Control Diagnostics

462-00 (Not Flashing) Coolant Inlet Pressure High Alarm Level indicates the coolant inlet

pressure is above the maximum allowed. The ECM will display a constant diagnostic fault code.

462-00 (Flashing) Coolant Inlet Pressure High Shutdown Level indicates the coolant inlet pressure is above the maximum allowed. The ECM will display a flashing diagnostic fault codeand the engine will shut down.

NOTE: This is not a standard offering and requires a special Personality Module that can be programmed as either an alarm or a shutdown.

Figure 1: Coolant Inlet Pressure Switch Diagram

Figure 2: Coolant Inlet Pressure Switch Schematic




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Diagnostic Codes

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Functional Test




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The sensor is powered by Battery Power (18 to 32 VDC). The sensor receives power from battery positive and negative sourced from the ESS panel through wire S131.

Output Signal

The sensor outputs a PWM voltage signal to the CMS. The Duty Cycle varies with measured pressure. The valved signal range is from about 24 percent to 90 percent. The frequency of the

signal is 5000 Hz.

kPa = (PWM percent -3.38) x 4.848

Control Diagnostics

109-01 (Not Flashing) Low Coolant Outlet Pressure Alarm Level indicates the Coolant OutletPressure is below an acceptable level. The ECM will display a constant diagnostic code.

109-01 (Flashing) Low Coolant Outlet Pressure Shutdown Level indicates the Coolant OutletPressure is below an acceptable level. The ECM will display a Flashing diagnostic fault code and

engine will shut down.

109-12 (Flashing) Coolant Outlet Pressure Sensor Failure Shutdown Level indicates theCoolant Outlet Pressure Sensor has provided data outside the range expected from a properlyfunctioning sensor for a certain period of time. The ECM will display a Flashing diagnostic faultcode and the engine will shut down.

Figure 1: Coolant Outlet Pressure Sensor Diagram




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Figure 2: Coolant Outlet Pressure Sensor Schematic

Figure 3: Coolant Outlet Pressure Sensor Table




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Diagnostic Codes




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Functional Test




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Manifold Air Pressure Sensor

System Operation

The Manifold Air Pressure Sensor provides an absolute inlet air manifold pressure to the EngineControl Module (ECM). The ECM uses the Air Pressure along with Fuel Pressure, FuelTemperature and Engine rpm to calculate the amount of fuel and airflow through the engine. TheECM monitors the air pressure for the air to fuel ratio control.

The Manifold Air Pressure can be read from the DDT or from the CMS Module.

The sensor is powered from the 20 or 24 VDC supply from the ECM. The 20 VDC supply isshared with other sensors.

The sensor outputs a PWM signal to the ECM. The signal level varies with measured pressure.The valid signal range is from approximately 17.3 percent to 95 percent duty cycle.

Control Diagnostics




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106-01 Insufficient Boost Pressure Alarm indicates the engine is unable to attain maximum power because of insufficient air supply to the inlet manifold and the engine is unable to achievethe desired air pressure for steady state operation within a reasonable period of time. Sufficient

pressure may be available to continue engine operation however fuel consumption and emissionsmay be compromised.

106-01 Insufficient Boost Pressure Alarm indicates the engine is unable to achieve the

minimum permissible air pressure for steady state operation within a reasonable period of time.Fuel flow will be reduced to achieve an acceptable air-to-fuel ratio to compensate; however theengine will shut down.

NOTE: The alarm code will often occur on a failed engine start for any reason. If the problem becomes more severe, the ECM will reduce fuel and indicate a boost (106-12) Manifold AirPressure Sensor Fault.

106-12 Manifold Air Pressure Sensor Failure indicates the Manifold Air Pressure Sensor has provided data outside the range expected from a properly functioning sensor or the control systemhas detected a failure in the indicated manifold air pressure likely caused by a sensor failure.

Figure 1: Air/Fuel Pressure Sensor Diagram

Figure 2: Air/Fuel Pressure Sensor Schematic




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Figure 3: Manifold Air Pressure Sensor Output Table




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Diagnostic Codes




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Functional Test




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Pressure Module Failure

System Operation

The Pressure Module provides Pulse Width Modulated (PWM) voltage signals corresponding tomanifold air pressure and fuel pressure respectively. The module receives power from the+20VDC Supply from the Engine Control Module (ECM).

The ECM monitors the inlet manifold air pressure and fuel manifold pressure for air-to-fuel ratiocontrol and power limiting. This module is essential to proper function of the engine.

Control Diagnostic 518-12

Pressure Module Failure Shutdown indicates that both sensors have provided data outside therange expected from properly functioning components.

Figure 1: Pressure Module Failure Diagram




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Figure 2: Air/Pressure Sensor Schematic




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Crankcase Pressure Sensor

System Operation

The Crankcase Pressure Sensor provides the pressure data (positive or negative) in the crankcaseto the Engine Control Module (ECM). The ECM monitors the crankcase pressure to protect theengine. In most applications excessive crankcase pressure will result in a shutdown: however, insome limited applications crankcase pressure may be an alarm only. The Crankcase Pressure can

be read from the CMS Gauge Module.

Sensor Supply

The sensor is powered from the 10 VDC Supply from the ECM. This supply is shared with severalother sensors.

Output Signal

The sensor outputs a DC voltage signal to the ECM. The DC voltage level varies with measured pressure. The valid voltage range is from about 0.3 to 9.7 VDC. The signal can be interpreted as pressure.

(kPa) = [Signal (VDC) 4.2] X 0.4

Control Diagnostics

519-00 (Not Flashing) Crankcase Pressure Alarm Level

If the crankcase pressure exceeded the programmed parameter for a certain period of time. TheECM will display a constant diagnostic code.

519-00 (Flashing) Crankcase Pressure Shutdown Level

If the crankcase pressure exceeded the programmed parameter for a certain period of time. The

ECM will display a flashing diagnostic code and the engine will shut down.

519-12 (Flashing) Crankcase Pressure Sensor Failure




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Diagnostic Codes




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Functional Test




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Starting Air Pressure Sensor

System Operation

The Starting Air Pressure Sensor provides a linear pulse width modulating (PWM) voltage signal(5 kHz) corresponding to the pressure available to the starting motor control valve. The StartingAir Pressure can be read from the CMS Gage module (Gage 12). The sensor receives power fromthe system battery. Although this sensor (or data) is read by the CMS Module, the sensor dataoutput is relayed via the CAT Data Link to the ECM and processed. The ECM performs thediagnostics associated with this sensor.

Output Signal

The output is a PWM signal that varies from 7 percent to 90 percent duty cycle.

kPa = (PWM percent -7) x 35

Figure 1: Starting Air Pressure Sensor Diagram




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Figure 2: Starting Air Pressure Sensor Schematic

Figure 3: Starting Air Pressure Sensor Output Table




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Diagnostic Codes




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Functional Test




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Fuel Pressure Sensor

System Operation

The Fuel Pressure Sensor provides the pressure difference between the fuel manifold and the airmanifold to the Engine Control Module (ECM). The ECM uses the fuel pressure along with air

pressure, fuel temperature and engine speed to calculate the amount of fuel flow through theengine. The fuel pressure can be read from the DDT.

The Fuel Pressure Sensor measures the differential pressure between the fuel manifold and the airmanifold. Expected output is a positive pressure anytime the engine is running (necessary for thereto be fuel flow into the engine). The fuel pressure line is a hose or metal line running from the fuelmanifold to the pressure transducer. The sensor is powered from the 20 VDC supply from the

ECM. The supply is shared with several other sensors.

Output Signals




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Figure 2: Air/Fuel Pressure Sensor Schematic


Figure 3: Fuel Pressure Sensor Output Table




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Diagnostic Codes




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Functional Test




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Oil Pressure Sensors

System OperationThe ECM measures both the filtered and unfiltered oil pressure. The ECM calculates thedifferential pressure by subtracting the filtered pressure from the unfiltered pressure. The ECMmonitors engine oil deferential pressure to provide a means of monitoring the status of the oilfilters. The differential oil pressure is displayed on the CMS Gage Module (gage 7).

NOTE: When the engine is shut down a sufficient conditions exist to ensure that no oil pressure is present, the ECM calibrates the two sensors to correct any error associated with inaccuracies ofeither sensor.

Sensor Supply

The sensors are powered by the battery (18 to 32 VDC) and receives power from battery positiveand negative sourced from the ESS Panel and provides its signal back to the ESS Panel.




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Output Signal

The sensor outputs a PWM voltage signal to the CMS. The Duty Cycle varies with measured pressure. The valid signal range is from about 10 to 90 percent. The frequency of the signal is5000 Hz.

kPa=(PWM(%) - 9) X 9.31

Control Diagnostics

541-00 (Not Flashing) High Differential Oil Pressure Alarm Level indicates the DifferentialOil Pressure data is above the range expected and the ECM will display a constant diagnosticcode.

541-00 (Flashing) High Differential Oil Pressure Shutdown Level indicates the Differential OilPressure data is above the range expected for a certain period of time. The ECM will display aflashing diagnostic code and the engine will shut down.

541-12 (Not Flashing) Unfiltered Oil Pressure Alarm Levels indicates the Unfiltered OilPressure data is above or below the range expected and the ECM will display a constant diagnosticcode.

541-12 (Flashing) Unfiltered Oil Pressure Shutdown Level indicates the Unfiltered OilPressure data is above or below the range expected for a certain period of time. The ECM willdisplay a flashing diagnostic code and the engine will shut down.

543-12 (Not Flashing) Filtered Oil Pressure Alarm Level indicates the Filtered Oil Pressuredata is above or below the range expected and the ECM will display a constant diagnostic code.

543-12 (Flashing) Filtered Oil Pressure Shutdown Level indicates the Filtered Oil Pressure data

is above or below the range expected for a certain period of time. The ECM will display a flashingdiagnostic code and the engine will shut down.

Figure 1: Oil Pressure Sensor Diagram




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Figure 2: Oil Pressure Sensor Schematic

Figure 3: Oil Pressure Sensor Output Table




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Diagnostic Codes




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Functional Test




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Oil Pressure Prelubrication Switch

System Operation

The ESS monitors the oil pressure and provides a switch output to the ECM indicating if oil pressure is below the programmed pressure of the switch.




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Although this sensor (or data) is read by the CAT Data Link to the ECM and processed. The ECM performs the diagnostics associated with this sensor.

The Oil Pressure Prelubrication Switch provides an open contact when the pressure is below theminimum acceptable pressure trip point. If oil pressure is below 7 kpa (1 psi), the switch is closed.

Control Diagnostics

584-05 (Not Flashing) Prelubrication Oil Pressure Alarm Level

If the oil pressure during prelube is below the minimum allowed after the prelube oil pressureswitch has been closed for 5 seconds, the ECM will display this diagnostic code.

584-05 (Flashing) Prelubrication Oil Pressure Switch Low Shutdown If the engine is runningand the prelube pressure switch opens or fails the ECM will display this code.

Figure 1: Oil Pressure Prelubrication Switch Diagram

Figure 2: Oil Pressure Prelubrication Switch Schematic




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Diagnostic Codes




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Fuel (Quality) Energy Content Input

System Operation

The ECM monitors the Fuel Energy Content for air-to-fuel ratio control and power limiting. Theengine control systems relies on sensor readings, combustion probes and buffers, and on themanual setting of the Fuel Energy Potentiometer to maintain consistent combustion and achievingthe best performance and emissions.

The Fuel Energy Content signal may be provided either by the Fuel Energy Content Potentiometer and Fuel Energy Content Buffer located in the ESS panel, or it may be provided by one of severalremote mounted modules.

Sensor Supply

The Fuel Energy Content input is a pulse width modulated (PWM) voltage signal corresponding to

the user input or present fuel energy content. The sensor (potentiometer) is powered from the 20VDC Supply from the ECM. This voltage supply is shared with several other sensors.

Output Signal

The buffer outputs a PWM signal to the ECM. The signal level varies with energy content (lowheat value). Minimum expected input from the buffer is about 10 percent PWM and maximumexpected PWM is about 90 percent. The failure is detected on complete loss of PWM signal. Thevalid signal range is from approximately 5 to 95 percent duty cycle.

Control Diagnostics

522-12 Fuel (Quality) Energy Content Input Failure Shutdown Indicates the potentiometer/buffer system has provided data outside the normal range expected from a properly




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functioning buffer or the control system has detected a failure in Indicated Fuel (Quality) EnergyContent likely caused by a buffer failure.

Figure 1: Fuel (Quality) Energy Content Input Diagram

Figure 2: Fuel (Quality) Energy Content Input Schematic




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Functional Test




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Fuel (Quality) Energy Content




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System Operation

The engine control system uses two methods for controlling the air-to-fuel ratio of the G3600Engine. The first method (open loop) uses pressures, temperatures and the Fuel Energy ContentSetting to calculate the air-to-fuel ratio of the engine. This method relies on sensor readings andon the manual setting of the Fuel Energy Potentiometer. The second method uses the combustion

feedback system to monitor how the air and fuel actually burned in the combustion chamber. Thismethod relies on the combustion probes and buffers. The actual air-to-fuel ratio that is used forcontrol is the combination of the two. A basic air-to-fuel ratio is calculated using the first methodand the second method creates a correction factor that compensates for any errors in the first,maintaining consistence combustion and achieving the best performance and emissions. The ECMmonitors the combustion characteristics of the fuel using the combustion sensors and combustion

buffers to maintain proper engine air-to-fuel ratio for emissions, fuel consumption and engine protection. The ECM requires that a minimum of one-half of the cylinders provide acceptablefeedback in order to permit fuel quality correction. Without acceptable feedback, the controlsystem is unable to compensate for changes in fuel quality, and result in an engine shutdown for

protection. The ECM also requires that the fuel correction factor remain within a particular rangewhile the engine is running. The correction factor from the combustion feedback system isdisplayed on the CMS Gage Module (gage 3) and the DDT. The Fuel (Quality) Energy Contentcan be read from the DDT and the ECM.

Control Diagnostics

529-00 Low Fuel (Quality) Energy Content Setting Limit Alarm indicates that the combustionfeedback system has adjusted the fuel correction factor to a level that is higher than normal or theFuel Correction Factor exceeds the High Fuel Correction Factor Level. This indicates there is a

problem associated with one of the two air-to-fuel measuring techniques. Engine load capabilitiesare affected.

529-01 High Fuel (Quality) Energy Content Setting Limit Alarm indicates that the combustionfeedback system has adjusted the fuel correction factor to a level that is lower than normal or theFuel Correction Factor is below the Low Fuel Correction Factor Level. This indicates there is a

problem associated with one of the two air-to-fuel measuring techniques.

529-02 Fuel (Quality) Energy Compensation Failure indicates one of two conditions or events.Case 1: That more than one-half of the total number of cylinder have one of the followingdiagnostic codes 501-02 through 516-02 Cylinder Misfire Greater Than 20 percent 501-08 through516-08 Cylinder Continuously Misfiring 501-13 through 516-13 Prechamber Out of Calibration.Case 2: All of the cylinders are not receiving a primary magneto firing pulse (501-09 through 516-09 Ignition failure).

529-13 Fuel (Quality) Energy Content Out of Range indicates that the combustion feedbacksystem has adjusted the fuel correction factor to a level that indicates that actual fuel energy isoutside the range that the engine can properly burn. This engine is designed to operate on fuelswith combustion characteristics defined by a Fuel Supply Minimum Level and a Fuel SupplyMaximum Level.

Figure 1: Fuel (Quality) Energy Content Input Diagram




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Diagnostic Codes




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Functional Test

ECM Speed Sensor

System Operation

The ECM Engine Speed Sensor (MPU) is a magnetic pickup sensor, which generates its outputsignal from the flywheel teeth. The speed sensor signal is used to accurately govern the enginespeed. This magnetic pickup is a three wire, powered, type of sensor and does not work like a two




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wired magnetic pickup. The Engine Speed Sensor must be installed with a one-half to three-quarters turn air gap. A properly adjusted air gap will prevent nuisance diagnostics.

Sensor Supply

The sensor is powered from the + 10 VDC Supply from the ECM. This voltage supply is sharedwith the Jacket Water Temperature Sensor, Fuel Temperature Sensor, and Crankcase Pressure

Sensor.

Output Signal

The sensor outputs an alternating type signal whose frequency varies directly to the speed of theengine. The signal level varies between 0 and 10 volts. Each pulse in the signal corresponds to the

passing of a ring gear tooth. The ring gear on the G3600 has 255 teeth resulting in 255 pulses forevery engine revolution. The signal can be interpreted as

engine speed (RPM)=frequency (Hz)/255 X 60.

The frequency of this signal can be measured using a voltmeter with an AC frequency mode or anoscilloscope.

Figure 1: ECM Speed Sensor Diagram




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Figure 2: ECM Speed Sensor Schematic




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Figure 3: ECM Speed Sensor Output Table




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Functional Test




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Figure 4: Speed Sensor Output Table




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Desired Speed Input

System Operation

The ECM monitors the Desired Speed to determine the speed at which to govern the engine.

The Desired Speed signal may be provided either by the Desired Speed Potentiometer and Desired Speed Buffer located in the ESS panel, or it m

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