C123B

C123B-EXCESSIVE DUMP FAULT

For a complete wiring diagram Consult Diagrams/Electrical.

- When Monitored:
Ignition on.

- Set Condition:
If more than 16 dump pulses in a row are detected without wheel speed recovery, this DTC will be set to active.





Diagnostic Test

1. BRAKE SYSTEM MECHANICAL CONDITION
Inspect the front and rear brakes for a mechanical condition that would cause any wheel(s) to lock-up during braking.
Inspect the Parking Brake to make sure it releases properly.
Were any problems found?

Yes

- Repair the braking system as necessary.
- Perform ABS VERIFICATION TEST.ABS Verification Test

No

- Go To2

2. TONE WHEEL
Inspect each Tone Wheel for damage, missing teeth or looseness.

NOTE: The Tone Wheel Teeth should be perfectly square, not bent or nicked.

Were any problems found?

Yes

- Replace the Tone Wheel as necessary.
- Perform ABS VERIFICATION TEST.ABS Verification Test

No

- Go To3

3. WHEEL BEARING
Inspect each wheel bearing for excessive run out or improper clearance.
Were any problems found?

Yes

- Repair or replace the wheel bearing(s) as necessary.
- Perform ABS VERIFICATION TEST.ABS Verification Test

No

- Go To4

4. WHEEL SPEED SENSOR WIRING HARNESS AND CONNECTORS
Start the engine.
With the scan tool, monitor the output of each Wheel Speed Sensor.
Raise and properly support the vehicle.

WARNING: BE SURE TO KEEP HANDS, FEET AND CLOTHING CLEAR OF ROTATING COMPONENTS.

Allow the drive wheels to rotate.
Rotate the non-driven wheels by hand.
Wiggle test the Wheel Speed wiring harnesses and connectors.
Look for any excessive variations in sensed wheel speed.
Were any problems found?

Yes

- Repair the wiring harness or connectors as necessary.
- Perform ABS VERIFICATION TEST.ABS Verification Test

No

- Go To5

5. LOADED WHEEL BEARING/SUSPENSION CONCERN

CAUTION: Make sure that the vehicle has braking capability before performing a road test.

NOTE: Have an assistant drive the vehicle while monitoring the scan tool.

With the scan tool, monitor the output of each Wheel Speed Sensor.
Road test vehicle so wheel bearings and suspension are loaded.
Look for any excessive variations in sensed wheel speed.
Were any problems found?

Yes

- Repair as necessary.
- Perform ABS VERIFICATION TEST.ABS Verification Test

No

- Replace the Hydraulic Control Unit.
- Perform ABS VERIFICATION TEST.ABS Verification Test