C102A

C102A-LEFT REAR WHEEL SPEED COMPARATIVE PERFORMANCE

For a complete wiring diagram, refer to the Wiring Information Electrical Diagrams.

- When Monitored:
With the ignition on.

- Set Condition:
When the Left Rear Wheel Speed Sensor (WSS) reading is different from the readings received from the other sensors at a vehicle speed above 40 km/h (25 mph). The Anti-Lock Brake Module compares WSS readings from side-to-side on an axle and front-to-rear.





1. CHECK FOR DTC C102A-LEFT REAR WHEEL SPEED COMPARATIVE PERFORMANCE

NOTE: This DTC must be active for the results of this test to be valid.

1. Turn the ignition on.
2. With the scan tool, record and erase DTCs.

CAUTION: Make sure brake capability is available before road testing.

3. Road test the vehicle over 40 km/h (25 mph).

NOTE: Vehicle must be driven above 40 km/h (25 mph) for set conditions to be met.

4. With the scan tool, read DTCs.

Does the scan tool display: C102A-LEFT REAR WHEEL SPEED COMPARATIVE PERFORMANCE active?

Yes

- Go To 3

No

- Go To 2

2. CHECK WHEEL SPEED SENSOR SIGNALS
1. Turn the ignition on.
2. With the scan tool, monitor and graph ALL the WSS speeds and compare graph while an assistant drives the vehicle.

NOTE: If graph shows periodic dropouts pay close attention to the tone wheel.

3. Slowly accelerate as straight as possible from a stop to 40 km/h (25 mph).

Is the Left Rear WSS speed showing 0 km/h (0 mph) or not matching other wheels or showing erratic behavior?

Yes

- Go To 3

No

- The condition that caused the symptom is currently not present. Inspect the related wiring for a possible intermittent condition. Look for any chafed, pierced, pinched, or partially broken wires.
- Perform the ABS-INTERMITTENT CONDITION TEST. ABS Intermittent Condition Test.

3. CHECK FOR IMPROPER LEFT REAR TIRE PRESSURE/MISMATCHED TIRES
1. Turn the ignition off.
2. Check and adjust the Left Rear Tire pressure.
3. Check and adjust all other tire pressures.
4. Inspect for mismatched tires on vehicle.

Is the Left Rear Tire improperly inflated or mismatched tires on vehicle?

Yes

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

No

- Go To 4

4. CHECK AXLE SHAFT FASTENER HARDWARE FOR LOOSENESS
1. Inspect the axle shaft fastener for looseness, and not properly fastened. Tighten fastener to proper specification as required.

Was the Axle Shaft fastener loose?

Yes

- Repair as necessary.

No

- Go To 5

5. CHECK LEFT REAR WSS LOOSENESS, INSPECT B3, B4 CIRCUITS/TERMINALS FOR DAMAGE

NOTE: Check all terminals for broken, bent, pushed out, or corroded terminals

1. Inspect the Anti-Lock Brake Module harness connector, Left Rear WSS, and Left Rear WSS harness connector.
2. Inspect the Left Rear WSS for looseness, excessive corrosion and not properly fastened.
3. Inspect the (B3) Left Rear WSS Signal and (B4) Left Rear WSS Supply circuits between the Left Rear WSS and Anti-Lock Brake Module for damage.

Is the Left Rear WSS loose or any of the wiring/connectors/terminals damaged?

Yes

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

No

- Go To 6

6. CHECK LEFT REAR WHEEL SPEED SENSOR FOR DAMAGE
1. Remove the Left Rear Wheel Speed Sensor
2. Inspect the Left Rear Wheel Speed Sensor face for damage.

Is the Left Rear Wheel Speed Sensor damaged?

Yes

- Replace sensor and hub assembly.
- Perform ABS VERIFICATION TEST. ABS Verification Test.

No

- Go To 7

7. CHECK LEFT REAR TONE WHEEL FOR DAMAGE
1. Inspect the Left Rear Tone Wheel for damage, missing teeth, cracks, corrosion or looseness.

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

Is the Left Rear Tone Wheel damaged?

Yes

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

No

- Go To 8

8. LEFT REAR WHEEL SPEED SENSOR
1. Replace the Left Rear Wheel Speed Sensor.
2. Perform ABS VERIFICATION TEST. ABS Verification Test.
3. Road test the vehicle over 40 km/h (25 mph).

NOTE: Vehicle must be driven above 40 km/h (25 mph) for set conditions to be met.

4. With the scan tool, read ABS DTCs.

Did DTC C102A-LEFT REAR WHEEL SPEED COMPARATIVE PERFORMANCE reset?

Yes

- Replace the Anti-Lock Brakes Module.
- Perform ABS VERIFICATION TEST. ABS Verification Test.

No

- Test Complete.