Diagnostic Test

Turn the ignition on.

With the scan tool, record and erase DTCs.

Cycle the ignition switch from off to on.

With the scan tool, read DTCs.

Does the scan tool display: C1020-LEFT REAR WHEEL SPEED SENSOR CIRCUIT? 

Yes 

1. Go To Step  2).

No 

1. 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.
2. Refer to the ABS-INTERMITTENT CONDITION TEST. (Refer to BRAKES - DIAGNOSIS AND TESTING - ABS-INTERMITTENT CONDITION) .

Turn the ignition off.

Inspect the Anti-Lock Brake Module harness connector, Left Rear WSS, and Left Rear WSS harness connector.

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

Yes 

1. Repair as necessary.
2. Perform ABS VERIFICATION TEST. (Refer to BRAKES - STANDARD PROCEDURE - ABS VERIFICATION TEST)  .

No 

1. Go To Step  3).

Fig 1: CHECKING (B4) LEFT REAR WSS 12 VOLT SUPPLY CIRCUIT VOLTAGE

Courtesy of DAIMLERCHRYSLER CORP.

Disconnect the Left Rear WSS harness connector.

Turn the ignition on.

Measure the voltage of the (B4) Left Rear WSS 12 Volt Supply circuit.

Is the voltage above 10.0 volts? 

Yes 

1. Go To Step  6).

No 

1. Go To Step  4).

Fig 2: CHECKING (B4) LEFT REAR WSS 12 VOLT SUPPLY CIRCUIT FOR A SHORT TO GROUND

Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the Left Rear WSS harness connector.

Disconnect the Anti-Lock Brake Module harness connector.

Using a 12-volt test light connected to 12-volts, probe the (B4) Left Rear WSS Supply circuit.

Does the test light illuminate brightly? 

Yes 

1. Repair the (B4) Left Rear WSS Supply circuit for a short to ground.
2. Perform ABS VERIFICATION TEST. (Refer to BRAKES - STANDARD PROCEDURE - ABS VERIFICATION TEST)  .

No 

1. Go To Step  5).

Fig 3: CHECKING (B4) LEFT REAR WSS 12 VOLT SUPPLY CIRCUIT FOR OPEN

Courtesy of DAIMLERCHRYSLER CORP.

Connect a jumper wire between ground and the (B4) Left Rear WSS Supply circuit in the Anti-Lock Brakes Module harness connector.

Using a 12-volt test light connected to 12-volts, probe the (B4) Left Rear WSS Supply circuit.

Does the test light illuminate brightly? 

Yes 

1. Replace the Anti-Lock Brakes Module in accordance with the Service Information.
2. Perform ABS VERIFICATION TEST. (Refer to BRAKES - STANDARD PROCEDURE - ABS VERIFICATION TEST)  .

No 

1. Repair the (B4) Left Rear WSS Supply circuit for an open.
2. Perform ABS VERIFICATION TEST. (Refer to BRAKES - STANDARD PROCEDURE - ABS VERIFICATION TEST)  .

Fig 4: CHECKING (B3) LEFT REAR WSS SIGNAL CIRCUIT FOR SHORT TO GROUND

Courtesy of DAIMLERCHRYSLER CORP.

Using a 12-volt test light connected to 12-volts, probe the (B3) Left Rear WSS Signal circuit.

Does the test light illuminate brightly? 

Yes 

1. Repair the (B3) Left Rear WSS Signal circuit for a short to ground.
2. Perform ABS VERIFICATION TEST. (Refer to BRAKES - STANDARD PROCEDURE - ABS VERIFICATION TEST)  .

No 

1. Go To Step  7).

Fig 5: CHECKING (B3) LEFT REAR WSS SIGNAL CIRCUIT FOR SHORT TO GROUND

Courtesy of DAIMLERCHRYSLER CORP.

Connect a jumper wire between ground and the (B3) Left Rear WSS Signal circuit in the Anti-Lock Brakes Module harness connector.

Using a 12-volt test light connected to 12-volts, probe the (B3) Left Rear WSS Signal circuit.

Does the test light illuminate brightly? 

Yes 

1. Go To Step  8).

No 

1. Repair the (B3) Left Rear WSS Signal circuit for an open.
2. Perform ABS VERIFICATION TEST. (Refer to BRAKES - STANDARD PROCEDURE - ABS VERIFICATION TEST)  .

Fig 6: CHECKING (B3) LEFT REAR WSS SIGNAL CIRCUIT FOR SHORT TO VOLTAGE

Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition on.

Remove all jumper wires.

Using a 12-volt test light connected between the (B3) Left Rear WSS Signal circuit and ground.

Does the test lioght illuminate brightly? 

Yes 

1. Repair the (B3) Left Rear WSS Signal circuit for a short to voltage.
2. Perform ABS VERIFICATION TEST. (Refer to BRAKES - STANDARD PROCEDURE - ABS VERIFICATION TEST)  .

No 

1. Go To Step  9).

Fig 7: CHECKING (B3) LEFT REAR WSS SIGNAL CIRCUIT AND (B4) LEFT REAR WSS 12 VOLT SUPPLY CIRCUIT SHORTED TOGETHER

Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Measure the resistance between the (B3) Left Rear WSS Signal circuit and the (B4) Left Rear WSS Supply circuit.

Is the resistance above 5.0 ohms? 

Yes 

Go To Step  10).

No 

1. Repair the (B3) Left Rear WSS Signal circuit and the (B4) Left Rear WSS Supply circuit for a short together.
2. Perform ABS VERIFICATION TEST. (Refer to BRAKES - STANDARD PROCEDURE - ABS VERIFICATION TEST)  .

Replace the Left Rear Wheel Speed Sensor in accordance with the Service Information.

Perform ABS VERIFICATION TEST. (Refer to BRAKES - STANDARD PROCEDURE - ABS VERIFICATION TEST)  .

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

With the scan tool, read ABS DTCs.

Did DTC C1020-LEFT REAR WHEEL SPEED SENSOR CIRCUIT reset? 

Yes 

1. Replace the Anti-Lock Brakes Module in accordance with the Service Information.
2. Perform ABS VERIFICATION TEST. (Refer to BRAKES - STANDARD PROCEDURE - ABS VERIFICATION TEST)  .

No 

1. Test Complete.