C1020

C1020 - LEFT REAR WHEEL SPEED SENSOR CIRCUIT






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

- When Monitored:
With the ignition on.

- Set Condition:
When the Left Rear Wheel Speed Sensor circuit fails the diagnostic test.






DIAGNOSTIC TEST

1. CHECK FOR DTC C1020 - LEFT REAR WHEEL SPEED SENSOR CIRCUIT






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 DTC's.
3. Cycle the ignition switch from off to on.
4. With the scan tool, read DTC's.

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

Yes
- Go To 2.

No
- Refer to the Intermittent Condition Diagnostic Procedure.
- Perform ABS Verification Test-VER 1. Refer to ABS Verification Test


2. CHECK CONNECTOR/TERMINAL FOR DAMAGE






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


1. Turn the ignition off.
2. 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
- Repair as necessary.
- Perform ABS Verification Test-VER 1. Refer to ABS Verification Test

No
- Go To 3.

3. CHECK (B4) LEFT REAR WSS SUPPLY CIRCUIT VOLTAGE







1. Turn the ignition off.
2. Disconnect the Left Rear WSS harness connector.
3. Turn the ignition on.
4. Measure the voltage between the (B4) Left Rear WSS Supply circuit and ground.

Is the voltage above 10 volts?

Yes
- Go to 6.

No
- Go To 4.

4. CHECK (B4) LEFT REAR WSS SUPPLY CIRCUIT SHORT TO GROUND






1. Turn the ignition off.
2. Disconnect the Anti-Lock Brake Module harness connector.
3. Disconnect the Left Rear WSS harness connector.
4. 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
- Repair the (B4) Left Rear WSS Supply circuit for a short to ground.
- Perform ABS Verification Test-VER 1. Refer to ABS Verification Test

No
- Go To 5.


5. CHECK (B4) LEFT REAR WSS SUPPLY CIRCUIT OPEN






1. Turn the ignition off.
2. Disconnect the Anti-Lock Brake Module harness connector.
3. Disconnect the Left Rear WSS harness connector.
4. Connect a jumper wire between the (B4) Left Rear WSS Supply circuit and ground.
5. 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
- Go to 6.

No
- Repair the (B4) Left Rear WSS Supply circuit for an open.
- Perform ABS Verification Test-VER 1. Refer to ABS Verification Test


6. CHECK (B3) LEFT REAR WSS SIGNAL CIRCUIT SHORT TO VOLTAGE






1. Turn the ignition off.
2. Disconnect the Left Rear WSS harness connector.
3. Turn the ignition on.
4. Measure the voltage between the (B3) Left Rear WSS Signal circuit and ground.

Is the voltage above one volt?

Yes
- Repair the (B3) Left Rear WSS Signal circuit for a short to voltage.
- Perform ABS Verification Test-VER 1. Refer to ABS Verification Test

No
- Go To 7.

7. CHECK (B3) LEFT REAR WSS SIGNAL CIRCUIT SHORT TO GROUND






1. Turn the ignition off.
2. Disconnect the Anti-Lock Brake Module harness connector.
3. Disconnect the Left Rear WSS harness connector.
4. 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
- Repair the (B3) Left Rear WSS Signal circuit for a short to ground.
- Perform ABS Verification Test-VER 1. Refer to ABS Verification Test

No
- Go To 8.

8. CHECK (B3) LEFT REAR WSS SIGNAL CIRCUIT OPEN






1. Turn the ignition off.
2. Disconnect the Anti-Lock Brake Module harness connector.
3. Disconnect the Left Rear WSS harness connector.
4. Connect a jumper wire between the (B3) Left Rear WSS Signal circuit and ground.
5. 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
- Go To 9.

No
- Repair the (B3) Left Rear WSS Signal circuit for an open.
- Perform ABS Verification Test-VER 1. Refer to ABS Verification Test

9. CHECK (B3) LEFT REAR WSS SIGNAL CIRCUIT AND (B4) LEFT REAR WSS SUPPLY CIRCUIT SHORT TOGETHER






1. Turn the ignition off.
2. Disconnect the Anti-Lock Brake Module harness connector.
3. Disconnect the Left Rear WSS harness connector.
4. 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 10.

No
- Repair the (B3) Left Rear WSS Signal circuit and the (B4) Left Rear WSS Supply circuit for a short together.
- Perform ABS Verification Test-VER 1. Refer to ABS Verification Test


10. CHECK LEFT REAR WSS






1. Turn the ignition off.
2. Reconnect all connectors.
3. Disconnect the Left Rear WSS harness connector.
4. Turn the ignition on.
5. Measure the voltage of the (B4) Left Rear WSS Supply circuit while reconnecting the Left Rear WSS harness connector.

Did the (B4) Left Rear WSS Supply circuit drop voltage to 0 volts?

Yes
- Replace the Left Rear WSS.
- Perform ABS Verification Test-VER 1. Refer to ABS Verification Test

No
- Go To 11.

11. CHECK LEFT REAR WSS OUTPUT






1. Turn the ignition off.
2. Reconnect all connectors.
3. Turn the ignition on.
4. Measure the amperage of the (B3) Left Rear WSS Signal circuit in the Left Rear WSS harness connector.
5. Slowly rotate the Left Rear wheel.

Does the amperage toggle between 7 mA to 14 mA?

Yes
- Go To 12.

No
- Replace the Left Rear WSS.
- Perform ABS Verification Test-VER 1. Refer to ABS Verification Test


12. ANTI-LOCK BRAKE MODULE INTERNAL FAULT - (B4) LEFT REAR WSS SUPPLY CIRCUIT






1. Turn the ignition off.
2. Remove the Anti-Lock Brake Module harness connector strain relief to access wires.
3. Reconnect the Anti-Lock Brake Module harness connector.
4. Turn the ignition on.
5. Measure the voltage between the (B4) Left Rear WSS Supply circuit and ground.

Is the voltage above 10 volts?

Yes
- Go To 13.

No
- Replace the Anti-Lock Brake Module.
- Perform ABS Verification Test-VER 1. Refer to ABS Verification Test


13. ANTI-LOCK BRAKE MODULE INTERNAL FAULT - (B3) LEFT REAR WSS SIGNAL CIRCUIT






1. Turn the ignition off.
2. Remove the Anti-Lock Brake Module harness connector strain relief to access wires.
3. Reconnect the Anti-Lock Brake Module harness connector.
4. Turn the ignition on.
5. Measure the voltage between the (B4) Left Rear WSS Supply circuit and the (B3) Left Rear WSS Signal circuit.

Is the voltage above 10 volts?

Yes
- Refer to Intermittent Condition Diagnostic Procedure.
- Perform ABS Verification Test-VER 1. Refer to ABS Verification Test

No
- Replace the Anti-Lock Brake Module.
- Perform ABS Verification Test-VER 1. Refer to ABS Verification Test