C102A JEEP, DODGE Left Rear Wheel Speed Comparative Performance

C102A JEEP, DODGE - When the Left Rear Wheel Speed Sensor (WSS) reading is difeerent from the readings received from the other sensors at a vehicle speed above 40 km/h (25 mph). The Antilock Brake System (ABS) Module compares WSS readings from side to side on an axle and front to rear.

Possible causes C102A code

• Left rear WSS loose B3 ,B4 circuit/connector/terminal damage.
• Improper left rear tire pressure/mismatched tires.
• Left rear tone wheel damage.
• Axle shaft fastener hardware.
• Left rear WSS.
• Antilock Brake System (ABS) Module.

Diagnose code C102A-Left Rear Wheel Speed comparative performance

Step 1. Check for DTC C102A-Left rear wheel speed comparative performance

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

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

Caution : Make sure braking 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 DTC.

Does the scan tool display C102A-Left rear wheel speed comparative performance active ?

YES, go to step 3.

NO, go to step 2.

Step 2. Check wheel speed sensor signal

1. Turn the ignition on.
2. With the scan tool, monitor and graph all the WSS speed 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 step 3.

NO, the condition that caused the symptom is currently not present. Inspect the related wiring for a possible intermittent condition. Lock for any chafed, pierced, pinched, or partially broken wires. Perform the ABS Intermittent condition.

Step 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 improperly inflated or mismatched tires on vehicle ?

YES, repair as necessary.
NO, go to step 4.

Step 4. Check axle shaft fastener hardware for looseness

1. Inspect the axle shaft fastener for looseness, and not properly fastened. Tighten fastener to properly specification as required.

Was the Axle Shaft fastener loose ?

YES, repair as necessary.
NO, go to step 5.

Step 5. Check Left Rear WSS looseness, inspect circuits/terminals for damage

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

1. Inspect the Antilock Brake System (ABS) 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 Left Rear WSS signal and Left Rear WSS supply circuits between the Left Rear WSS and Antilock Brake System (ABS) Module.

Is the Left rear WSS loose or any of the wiring/connector/terminals damaged ?

YES, repair as necessary.
NO, go to step 6.

Step 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 damage ?

YES, replace sensor and hub assembly.
NO, go to step 7.

Step 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 sould be perfectly square, not bent, or nicked.

Is the Left Rear tone wheel damage ?

YES, repair as necessary.
NO, go to step 8.

Step 8. Left Rear wheel speed sensor

1. Replace the Left Rear wheel speed sensor, 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.

2. With the scan tool, read ABS DTC.

Did DTC C102A-Left Rear wheel speed comparative performance reset ?

YES, replace the Antilock Brake System (ABS) Module. Perform the ABS Verification Test.
NO, test complete for DTC C102A-Left Raer wheel speed comparative performance.

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