anti-lock brake system[1]

8/9/2019 Anti-lock Brake System[1]

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ANTI-LOCK BRAKE SYSTEM

General Information

The Teves Mark IV-g Anti-lock Brake System (ABS) was an option on the

1996 Chrysler Minivan models. Beginning in 1997, these same models are

equipped with the Teves Mark 20 ABS system. Both of these ABS systems

operate in basically the same manner, however, they may use some different

components.

When conventional brakes are applied in an emergency stop or on ice, one or

more wheels may lock. This may result in loss of steering control and vehicle

stability. The purpose of the Anti-lock Brake System (ABS) is to prevent lock

up under heavy braking conditions. This system offers the driver increasedsafety and control during braking. Anti-lock braking operates only at speeds

above 3 mph (5 km/h).

Under normal braking conditions, the ABS functions the same as a standard

brake system with a diagonally split master cylinder and conventional

vacuum assist.

If wheel locking tendency is detected during application, the system will enter

anti-lock mode. During anti-lock mode, hydraulic pressure in the four wheel

circuits is modulated to prevent any wheel from locking. Each wheel circuit is

designed with a set of electrical valves and hydraulic line to providemodulation, although for vehicle stability, both rear wheel valves receive the

same electrical signal. The system can build or reduce pressure at each

wheel, depending on signals generated by the Wheel Speed Sensors (WSS) at

each wheel and received at the Controller Anti-lock Brake (CAB).

PRECAUTIONS

Failure to observe the following precautions may result in system damage:

Before performing electric arc welding on the vehicle, disconnect the

control module and the hydraulic unit connectors.

When performing painting work on the vehicle, do not expose the

control module to temperatures in excess of 185F (85C) for longer than 2

hours. The system may be exposed to temperatures up to 200F (95C) for

less than 15 minutes.

Never disconnect or connect the control module or hydraulic

modulator connectors with the ignition switch ON.

Never disassemble any component of the Anti-Lock Brake System

(ABS) which is designated unserviceable; the component must be replaced as

an assembly.

When filling the master cylinder, always use brake fluid which meetsDOT-3 specifications; petroleum-based fluid will destroy the rubber parts.


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Working on ABS system requires extreme amount of mechanical

ability, training and special tools. If you are not familiar have your vehicle

repaired by a certified mechanic or refer to a more advanced publication on

this subject.

Diagnosis and Testing

For the proper diagnostic procedure for either the entire ABS system or a

single component of the system, a scan tool (DRB or equivalent) is

necessary. Because of the complexity of the ABS system and the importance

of correct system functioning, it is a good idea to have a qualified automotive

mechanic test the system if any problems have been detected.

The self-diagnostic ABS start up cycle begins when the ignition switch is

turned to the ONposition. An electrical check is completed on the ABS

components, such as the wheel speed sensor continuity and other relay

continuity. During this check the amber anti-lock light is turned on for

approximately 1-2 seconds.

Further functional testing is accomplished once the vehicle is set in motion.

The solenoid valves and the pump/motor are activated briefly to verify

function

The voltage output from the wheel speed sensors is verified to be

within the correct operating range

If the vehicle is not set in motion within 3 minutes from the time the ignition

switch is set in the ONposition, the solenoid test is bypassed, but the

pump/motor is activated briefly to verify that it is operating correctly.

For the Teves Mark IV-g system fault codes are kept in a non-volatile

memory until either erased by the DRB or erased automatically after 50

ignition cycles (key ON-OFFcycles). The only fault that will not be erased

after the 50 ignition cycles is the CAB fault. On the Teves Mark 20 system,

DTCs are kept in the controller's memory until erased with the DRB scan tool,

or they are erased automatically after 3,500 miles or 255 key cycles which

ever occurs first. A CAB fault can only be erased by the DRB scan tool. More

than one fault can be stored at a time. The number of key cycles since the

most recent fault was stored is also displayed. Most functions of the CAB and

ABS system can be accessed by the DRB scan tool for testing and diagnostic

purposes.

To read the Diagnostic Trouble Codes (DTC's) perform the following:

1. Inspect the ABS components and connectors for damage and/or

proper connections. Keep in mind that the brake light circuit also provides an

input to to the ABS system. If the brake lights do not work, they must be fixed

before proceeding.

2. Connect a DRB or equivalent scan tool to the Data Link Connector

(located under the driver's side instrument panel). A scan tool must be used to

access these codes.

3. Turn the ignition to the ONposition. Wtih the scan tool, select "ABS".

4. Use the scan tool to select "Inputs/Outputs", and read the brake

switch status. While pressing on the brake pedal, check the scan tool display.


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Select "Read DTC" and record any trouble codes which may appear.

Sometimes, the cause of one trouble code may trigger additional codes to be

set. If more than one code appear, a certain sequence of tests may be

necessary. The beginning of each test will indicate if another test should be

performed first.

5. Once the problem is corrected, use the scan tool to erase the trouble

code(s).

Trouble Code Displays

The following is a list of the Teves Mark IVg Anti-lock Brake System (ABS)

trouble codes that the DRB (or equivalent) scan tool may display for 1996

Chrysler minivan models:

Diagnostic compare

Left front inlet valve

Left front outlet valve

Left front sensor circuit failure

Left front sensor continuity < 25 MPH

Left front sensor continuity > 25 MPH

Left front sensor signal missing

Left front sensor speed comparison

Left rear inlet valve

Left rear outlet valve

Left rear sensor circuit failure

Left rear sensor continuity < 25 MPH

Left rear sensor continuity > 25 MPH

Left rear sensor signal missing

Left rear sensor speed comparison

Pump motor circuit not working properly

Pump motor not running

Right front inlet valve

Right front outlet valve

Right front sensor circuit failure

Right front sensor continuity < 25 MPH

Right front sensor continuity > 25 MPH

Right front sensor signal missing

Right front sensor speed comparison

Right rear inlet valve

Right rear outlet valve

Right rear sensor circuit failure


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Right rear sensor continuity < 25 MPH

Right rear sensor continuity > 25 MPH

Right rear sensor signal missing

Right rear sensor speed comparison

System overvoltage

System undervoltage

Valve block feed failure

Valve power feed circuit

The following is a list of the Teves Mark-20 Anti-lock Brake System (ABS)

trouble codes that the DRB (or equivalent) scan tool may display for 1997-99

Chrysler minivan models:

CAB power feed circuit

CCD communication

Controller failure

Left front sensor circuit failure

Left front sensor signal failure

Left rear sensor circuit failure

Left rear sensor signal failure

Pump motor circuit not working properly

Right front sensor circuit failure

Right front sensor signal failure

Right rear sensor circuit failure

Right rear sensor signal failure

System overvoltage

System undervoltage

Wheel Speed Sensors

REMOVAL & INSTALLATION

One of the primary inputs to the ABS system is from the wheel speed

sensors. There is a sensor at each wheel that reads magnetic impulses from a

toothed gear-like tone wheel. The sensors are easily damaged and must be

handled with care. Make sure the wheel sensor surfaces are clean since they

are magnetic and attract metal chips and debris. Use care when removing,

installing and routing the sensor wiring. The wiring must be correctly installed

to avoid ABS problems later.

Front Wheel Sensor


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Remove the two screws that secure the mounting bracket and grommet retainer ...

... then pull the grommet down ...


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... and unplug the connector

Next, remove the bolt that secures the wheel sensor ...


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... and carefully remove it from the steering knuckle

The wheel sensor assembly can now be removed from the vehicle

1. Disconnect negative battery cable.

2. Carefully raise and safely support the vehicle. Remove the front wheel.

3. Remove the 2 mounting screws that attach the front channel bracket

and grommet retainer to the outer vehicle frame rail.

4. Pull the speed sensor cable grommet and wiring connector through

the hole in the strut tower. Disconnect the vehicle wiring harness connector

from the speed sensor connector. Be careful not to damage the pins on the

connector.

5. Remove the bolt that mounts the speed sensor head to the steering

knuckle.

6. Gently remove the speed sensor head from the steering knuckle.


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WARNING

Do not remove the speed sensor with pliers for any reason. If the speed sensor

has seized, due to corrosion, remove it with a small mallet and punch. Lightly

tap the edge of the sensor ear, rocking the sensor from side to side until it is

free.

7. Remove the speed sensor cable grommets from the retaining bracket.

8. Remove the wheel speed sensor from the vehicle.

To install:

9. Install the speed sensor head into the steering knuckle. Install the

mounting screw and torque to 105 inch lbs. (12 Nm).

10. Inspect the air gap between the face of the wheel speed sensor and

the top surface of the tone wheel. The air gap must be less than the maximum

allowable tolerance of 0.047 inch (1.2mm).

Correct system operation depends on the wheel speed sensor cables

being installed properly. Be sure the sensor cables are installed in the

retainers. Failure to do this could result in cable over extension

and/or contact with moving parts. This could result in an open circuit

and/or false sensor readings.

11. Install the speed sensor wiring grommets into the intermediate

retaining bracket on the strut assembly. Be sure the sensor cable is routed

correctly to the strut assembly on the rearward side of the stabilizer bar link.

12. Install the 2 mounting bolts that attach the channel bracket to the

vehicle frame. Torque the 2 bolts to 95 inch lbs. (11 Nm).

13. Install the channel bracket and grommet retainer onto the vehicle

frame rail. Be careful not to pinch the speed sensor cable under the channel

bracket.

14. Connect the wheel speed sensor connector to the vehicle wiring

harness connector. Be sure to securely latch the connector locking tab and

seat the connector properly.

15. Insert the sensor cable and cable grommet into the hole in the strut

tower.

16. Install the front wheel and lug nuts. Tighten the wheel lug nuts in a

star pattern sequence and torque the nuts to half specification. Then repeat

the lug nut torquing sequence to full specified torque of 95 ft. lbs. (129 Nm).

17. Lower the vehicle. Reconnect the negative battery cable.

18. Road test the vehicle to check the operation of the ABS and base

brake systems.

Rear Wheel Sensor


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Rear wheel speed sensor location (vehicles with drum brakes)

Rear wheel speed sensor location (vehicles with disc brakes)

The rear wheel speed sensor cable routing detail


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Remove the grommet in the floor pan to access the speed sensor cable connector

1. Disconnect the negative battery cable.

2. Carefully raise and safely support the vehicle. Remove the rear wheel.

3. Remove the speed sensor cable grommet, then the wiring harness

through the hole in the vehicle floor pan. Do NOT pull on the speed sensor

wiring when removing the grommet from the underbody.

4. Disconnect the speed sensor wiring connector from the vehicle wiring

harness. Be careful not to damage the pins of the wiring connectors. Also

inspect the connectors for any signs of previous damage.

5. Remove the speed sensor wiring from the rear brake flex hose routing

clips. Be careful to NOT damage the routing clips on the rear brake flex hose.

The routing clips are molded to the brake hoses and if they are damaged, the

brake flex hoses will require replacement.

6. If removing the right side rear speed sensor, remove the speed sensor

cable grommet from the axle flange, brake tube clip and routing clip from the

track bar bracket on the axle.

7. Remove the 2 rear speed sensor cable/brake tube routing clips and

then unclip the speed sensor cable from the routing clips on the rear brake

tube.

8. Remove the speed sensor head mounting bolt from the rear bearing.

Remove the wheel speed sensor head from the rear bearing assembly.

WARNING

Do not remove the wheel speed sensor with pliers for any reason. If the speed

sensor has seized, due to corrosion, remove it with a hammer and punch.

Lightly tap the edge of the sensor ear, rocking the sensor from side to side until

it is free.

9. Remove the wheel speed sensor from the vehicle.

To install:

10. Install the wheel speed sensor head into the rear wheel bearing

assembly. Be sure the plastic, anti-rotation pin is fully seated in wheel bearing


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flange before installing the mounting bolt. Install the mounting bolt and torque

to 105 inch lbs. (12 Nm).


the top surface of the tone wheel. The air gap must be less than the maximum

allowable tolerance of 0.047 inch (1.2mm).

12. Install the 2 routing brackets that secure the speed sensor cable and

brake tube to the rear axle. The speed sensor cable must be routedunderneath the brake tube. Be careful not to damage the brake hose routing

clips.

13. Install the speed sensor cable into the rear brake flex hose routing

clips.

14. If installing the right rear speed sensor cable, install the cable

grommet onto the rear axle brake flex hose bracket.

WARNING

The left and right rear wheel speed sensor connectors are keyed differently.

Therefore, when connecting a speed sensor cable to a vehicle wiring harness, do

NOT force the connectors together, or damage to the connectors will result.

15. Connect the speed sensor wiring connector to the vehicle wiring

harness and install the sensor cable grommet back into the wiring access

hole on the vehicle underbody. Be sure the speed sensor connector is fully

seated and locked into the vehicle wiring harness. Be sure the speed sensor

cable grommet is fully seated into the vehicle underbody wiring access hole.

16. Install the wheel and lug nuts. Tighten the wheel lug nuts in a star

pattern sequence and torque the nuts to half specification. Then repeat the lug

nut tightening sequence to full specified torque of 95 ft. lbs. (129 Nm).

17. Lower the vehicle to the ground.

18. Reconnect the negative battery cable. Road test the vehicle and check

for proper base and ABS braking system operation.

TESTING

1. Inspect the sensor and its connector. If the sensor looks damaged or

connector looks disengaged, repair it as necessary.

2. With the ignition key turned OFF, disengage the wheel speed sensor

connector. Inspect the condition of the terminals and repair as necessary.

3. Using an ohmmeter, measure the resistance between the wheel speedsensor connector terminals on the sensor side.

4. The resistance should measure 900-1300 ohms. If the resistance

measures outside this value, replace the wheel speed sensor.

5. Then, measure the resistance between either one of the wheel speed

sensor pins and ground on the sensor side.

6. If the resistance measures below 15k ohms, replace the wheel speed

sensor.

Controller Anti-lock Brakes (CAB)



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1996 Vehicles

on 1996 vehicles, the CAB unit is located under the instrument panel near the heater A/C duct

The CAB bracket is held in place by two nuts

The CAB is mounted under the instrument panel on the side of the

brake pedal bracket toward the center of the vehicle.

1. Turn the ignition switch OFF.


3. Loosen the retaining bolt, then unplug the 60-pin wiring harness

connector from the CAB.

4. Remove the 2 nuts attaching the CAB mounting bracket to the brake

pedal bracket, then remove the CAB from the vehicle.

To install:


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5. Install the CAB module and bracket assembly onto the brake pedal

bracket. Secure the CAB in place with the 2 mounting nuts. Tighten the

mounting nuts to 21 ft. lbs. (28 Nm).

6. Attach the 60-way connector to the CAB by hand as far as possible,

then use the CAB connector retaining bolt to fully seat the wiring harness

connector into the CAB.

7. Tighten the 60-way connector retaining bolt and tighten to 35 inch lbs.(4 Nm).

8. Connect the negative battery cable.

1997-99 Vehicles

On 1997-99 vehicles, the CAB (integrated with the Hydraulic Control Unit, or HCU) is located on

the front suspension cradle

Once the HCU is removed, the CAB can be removed


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The CAB can be separated from the HCU by removing the 4 mounting screws

The CAB is mounted to the bottom of the Hydraulic Control Unit

(HCU).


2. Using a brake pedal depressor, move and lock the brake pedal to a

position past its first 1 inch of travel. This will prevent brake fluid from

draining out of the master cylinder when the brake tubes are removed from

the proportioning valve.

3. Raise and safely support the vehicle securely on jackstands.

4. Disengage the 25-way wiring harness connector from the CAB by

grasping the lock on the connector and pulling it out from the connector as far

as it will go. This will remove the connector out from the CAB socket.

WARNING

Do not apply a 12 volt power source to any terminals of the 25-way connector

when it is disengaged.

5. To prevent possible hydraulic system contamination, thoroughly clean

the HCU and brake tubes. Use MOPAR Brake Parts Cleaner, or an equivalent

solvent.

6. Label and disconnect the chassis brake tubes from the inlet and outlet

ports of the HCU.

7. Remove the 3 bolts attaching the HCU mounting bracket to the front

suspension crossmember.

8. Remove the HCU and the mounting bracket as a unit from the vehicle.

9. Remove the 3 bolts mounting the HCU to the mounting bracket.

Separate the HCU from the mounting bracket.

10. Unplug the pump motor wiring harness from the CAB.

11. Loosen the 4 mounting bolts, then separate the CAB from the valve

block of the HCU.

To install:


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12. Place the CAB in position against the valve block of the HCU. Install

and tighten the 4 mounting bolts to 17 inch lbs. (2 Nm).

13. Plug the pump motor wiring harness into the CAB.

14. Install the HCU onto the mounting bracket and tighten the 3 mounting

bolts to 97 inch lbs. (11 Nm).

15. Place the HCU and mounting bracket assembly into position on thefront suspension crossmember and tighten the mounting bolts to 21 ft. lbs.

(28 Nm).

16. Install the chassis brake tubes into their correct port locations on the

HCU valve block. Tighten the brake tube fittings to 13 ft. lbs. (17 Nm).

17. Install the 25-way connector into the CAB socket. Install the connector

in the following manner:

1. Position the connector into the CAB

socket and carefully push it down as far as it

will go.

2. Once the connector is fully seated intothe socket, push in the connector lock as far as

it will go. This pulls the connector into the

socket which locks it in the installed position.

18. Install the routing clips onto the brake tubes.

19. Lower the vehicle.


21. Remove the brake pedal positioning tool from the vehicle.

22. Bleed the base brake system and the ABS hydraulic system.

23. Road test the vehicle to ensure proper operation of the base and ABS

systems.

Hydraulic Control Unit (HCU)


1996 Vehicles


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The HCU is located on the front suspension crossmember

The Hydraulic Control Unit (HCU) is located on the driver's side of the

vehicle, mounted onto the front suspension crossmember.

1. Disconnect and isolate the negative battery cable.

2. Disengage the HCU 10-way and 2-way connectors from the retaining

bracket. Then disengage the HCU 10-way and 2-way connectors from the

vehicle wiring harness located on the driver's side strut tower.

3. Disconnect the HCU wiring pigtail retaining straps from the master

cylinder brake tubes. There are 2 retaining straps, one above and one below,

the steel braid on the master cylinder tubes.

4. Using a brake pedal positioning tool, or equivalent, depress the brake

pedal past the first 1 inch of travel and hold in this position. This will isolate

the master cylinder reservoir from the brake hydraulic system, which will

prevent the brake fluid from draining out of the reservoir.


6. Using Brake Parts Cleaner, thoroughly clean all surfaces, brake line

fittings and connections to the HCU.

7. Label and disconnect the chassis brake tubes from the inlet and outlet

ports of the HCU.

8. Remove the 3 bolts attaching the HCU mounting bracket to the front

suspension crossmember.

9. Remove the HCU and the mounting bracket as a unit from the vehicle,

pulling the HCU wiring pigtail through the opened master cylinder tube clip

retaining straps.

To install:

10. Locate and lock the HCU wiring pigtail into the routing clips located on

the primary and secondary master cylinder-to-HCU brake tubes. When thewiring pigtail is installed in the routing clips, be sure that the brake tubes and

wiring harness do not touch any other components.


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11. Place the HCU and mounting bracket assembly into position on the

front suspension crossmember and tighten the mounting bolts to 21 ft. lbs.

(28 Nm).

12. Install the chassis brake tubes into their correct port locations on the

HCU valve block. Tighten the brake tube fittings to 13 ft. lbs. (17 Nm).


14. Engage the HCU 10-way and 2-way connectors into the vehicle wiring

harness connectors.

15. Install the HCU 10-way and 2-way connectors back into the bracket

located on the driver's side strut tower.


17. Remove the brake pedal positioning tool from the vehicle.

18. Bleed the base brake system and the ABS hydraulic system.

19. Road test the vehicle to ensure proper operation of the base and ABS

systems.

1997-99 Vehicles

Refer to the removal and installation procedures outlined under

Controller Anti-lock Brakes (CAB), earlier in this section.

Proportioning Valve


Proportioning valve detail for ABS-equipped vehicles

1. Using a brake pedal depressor, move and lock the brake pedal to a

position past its first 1 inch of travel. This will prevent brake fluid from

draining out of the master cylinder when the brake tubes are removed from

the proportioning valve.



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To prevent possible hydraulic system contamination, thoroughly

clean the proportioning valve and brake tubes. Use MOPAR Brake

Parts Cleaner, or an equivalent solvent.

3. Remove the 4 brake lines from the inlet and outlet ports of the

proportioning valve.

4. Remove the bolts securing the proportioning valve bracket to thevehicle frame rail. Remove the proportioning valve assembly from the vehicle.

To install:

5. Place the proportioning valve assembly into position on the frame rail.

Install the mounting bolts and tighten to 10 ft. lbs. (14 Nm).

6. Install the chassis brake lines into the proportioning valve assembly.

Tighten the brake line fittings to 12 ft. lbs. (16 Nm).

7. Bleed the brake system.


9. Carefully road test the vehicle to verify proper brake system operation.

Tone (Exciter) Ring


Rear Wheel (All Wheel Drive Only) and Front Wheel Tone Rings

The front ABS tone ring and rear ABS tone ring (All Wheel Drive only) are

integral components of the halfshaft assemblies and therefore, cannot be

serviced separately. If any of these tone rings require service, the halfshaft

assembly must be replaced.

However, the rear ABS tone ring on front wheel drive vehicles can be serviced

separately.

Rear Wheel (Front Wheel Drive Only)


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The rear tone wheel on front wheel drive vehicles must be removed with a special puller

Installing a tone wheel onto a new hub/bearing with an arbor press

1. Remove the rear wheel speed sensor from the rear hub/bearing flange.

2. Remove the rear wheel hub/bearing assembly from the vehicle.

3. Install 3 lug nuts on 3 of the wheel mounting studs to prevent possible

thread damage while installing the assembly in a bench vise. Using Puller

Special Tool C-4693, or equivalent, remove the tone wheel from the back of

the hub/bearing assembly.

To install:

4. Position the hub/bearing assembly in an arbor press supported by

Receiver Special Tool 6062A-3. Position Driver Special Tool 6908-1 with the

undercut side facing up on top of the tone wheel.

5. Press the tone wheel onto the hub/bearing assembly until it fits flush

with the end of the hub shaft.

6. Install the hub/bearing assembly onto the vehicle.

7. Install the rear wheel speed sensor onto the rear hub/bearing flange.


the top surface of the tone wheel. The air gap must be less than the maximumallowable tolerance of 0.047 inch (1.2mm).

9. Install the brake drum/rotor.

10. Install rear wheel(s).

11. Adjust the rear brakes.

Bleeding the ABS System

The bleeding procedure is a 2-step process, one of which will require use of

the DRB scan tool or its equivalent. Bleed the system as follows:

1. Locate the diagnostic connector under the dash panel to the left of the

steering column cover.


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2. Connect the DRB scan tool to the connector. Install the correct

cartridge for the Anti-Lock Brake systems. Check to make sure the CAB

(Controller Anti-lock Brakes) does not have any fault codes stored in it. If it

does, remove them using the DRB scan tool.

CAUTION

Be sure to always wear safety glasses when bleeding the brake system. This will

prevent personal injury to your eyes in case fluid squirts out at high pressure.

3. Bleed the base brake system using the non-ABS manual bleeding

method as outlined earlier in this section. Be sure to bleed the brake system

in the correct sequence.

4. Utilizing the scan tool, go to the "Bleed ABS" routine. Firmly apply the

brake pedal to initiate the "Bleed ABS" cycle one time. Release the brake

pedal.

5. Using the scan tool, go on to bleed the Anti-Lock Brake System

according to the scan tool literature.

6. Once bleeding with the scan tool is complete, repeat the conventional

bleed procedure for the base brake system.

7. Perform this procedure until the brake fluid flows clear and free of air

bubbles. Check brake fluid level periodically to prevent the reservoir from

running low on fluid. Top off the master cylinder reservoir to the proper level

with DOT 3 type brake fluid only.

8. Road test the vehicle to check for proper brake system operation.

Brake Specifications and Troubleshooting

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Chilton Automotive Information Systems. 2004 Thomson Delmar Learning.
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anti-lock brake system[1]

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