C1020

C1020-LEFT REAR WHEEL SPEED SENSOR CIRCUIT





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 circuit fails the 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 DTCs.
3. Cycle the ignition switch from off to on.
4. With the scan tool, read DTCs.

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

Yes

- Go To 2

No

- Perform the ABS-INTERMITTENT CONDITION TEST ABS Intermittent Condition 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 ABS Verification Test.

No

- Go To 3

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




1. Turn the ignition off.
2. Disconnect the Left Rear WSS harness connector.
3. Disconnect the Anti-Lock Brake Module 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 ABS Verification Test.

No

- Go To 4

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




1. 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 ABS Verification Test.

No

- Go To 5

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




1. Connect a jumper wire between ground and the (B4) Left Rear WSS Supply circuit in the Anti-Lock Brake Module harness connector.
2. 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 ABS Verification Test.

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




1. Connect a jumper wire between ground and the (B3) Left Rear WSS Signal circuit in the Anti-Lock Brake Module harness connector.
2. 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 7

No

- Repair the (B3) Left Rear WSS Signal circuit for an open.
- Perform ABS VERIFICATION TEST ABS Verification Test.

7. CHECK (B4) LEFT REAR WSS SIGNAL CIRCUIT SHORT TO VOLTAGE




1. Turn the ignition on.
2. Remove all jumper wires.
3. Measure the voltage between the (B4) Left Rear WSS Signal circuit and ground.

Is the voltage above one volt?

Yes

- Repair the (B4) Left Rear WSS Signal circuit for a short to voltage.
- Perform ABS VERIFICATION TEST ABS Verification Test.

No

- Go To 8

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




1. 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 ABS Verification Test.

No

- Go To 9

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




1. Turn the ignition off.
2. 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 ABS Verification Test.

10. LEFT REAR WHEEL SPEED SENSOR
1. Replace the Left Rear Wheel Speed Sensor.
2. Perform ABS VERIFICATION TEST ABS Verification Test.

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

3. Road test the vehicle over 25 mph (40 km/h).
4. With the scan tool, read ABS DTCs.

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

Yes

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

No

- Test complete.