C1020

C1020 - Left Rear Wheel Speed Sensor Circuit






For a complete wiring diagram, refer to.

• When Monitored: With the ignition ON.

• Set Condition: If the left rear wheel speed sensor circuit fails the diagnostic test.






Test Step 1 - Test for DTC C1020 - Left Rear Wheel Speed Sensor Circuit

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

• 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

• Go to Test Step 2 => [ Test Step 2 - Test Connector/Terminal for Damage ]

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.

• Refer to the ABS Intermittent Condition Test. Refer to => Non-DTC Based Diagnostics.

Test Step 2 - Test Connector/Terminal for Damage

• Test all terminals for broken, bent, pushed out, or corroded terminals.

• 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

• Repair as necessary.

• Perform ABS Verification Test. Refer to => Non-DTC
Based Diagnostics. ABS Verification Test

No

• Go to Test Step 3 => [ Test Step 3 - Test Left Rear WSS 12 Volt Supply Circuit Voltage ]

Test Step 3 - Test Left Rear WSS 12 Volt Supply Circuit Voltage






• Disconnect the left rear WSS harness connector.

• Turn the ignition ON.

• Measure the voltage of the left rear WSS 12 volt supply circuit.

Is the voltage more than 10.0 volts?

Yes

• Go to Test Step 6 => [ Test Step 6 - Test Left Rear WSS Signal Circuit for a Short to Ground ]

No

• Go to Test Step 4 => [ Test Step 4 - Test Left Rear WSS 12 Volt Supply Circuit for a Short
to Ground ]

Test Step 4 - Test Left Rear WSS 12 Volt Supply Circuit for a Short to Ground






• Turn the ignition OFF.

• Disconnect the left rear WSS harness connector.

• Disconnect the anti lock brake module harness connector.

• Using a 12 volt test lamp connected to 12 volts, probe the left rear WSS supply circuit.

Does the test lamp illuminate brightly?

Yes

• Repair the left rear WSS supply circuit for a short to ground.

• Perform ABS Verification Test. Refer to => Non-DTC
Based Diagnostics. ABS Verification Test

No

• Go to Test Step 5 => [ Test Step 5 - Test Left Rear WSS 12 Volt Supply Circuit for an Open ]

Test Step 5 - Test Left Rear WSS 12 Volt Supply Circuit for an Open






• Connect a jumper wire between ground and the left rear WSS supply circuit in the anti lock brakes module harness connector.

• Using a 12 volt test lamp connected to 12 volts, probe the left rear WSS supply circuit.

Does the test lamp illuminate brightly?

Yes

• Replace the anti lock brakes module.

• Perform ABS Verification Test. Refer to => Non-DTC
Based Diagnostics. ABS Verification Test

No

• Repair the left rear WSS supply circuit for an open.

• Perform ABS Verification Test. Refer to => Non-DTC
Based Diagnostics. ABS Verification Test

Test Step 6 - Test Left Rear WSS Signal Circuit for a Short to Ground






• Using a 12 volt test lamp connected to 12 volts, probe the left rear WSS signal circuit.

Does the test lamp illuminate brightly?

Yes

• Repair the left rear WSS signal circuit for a short to ground.

• Perform ABS Verification Test. Refer to => Non-DTC
Based Diagnostics. ABS Verification Test

No

• Go to Test Step 7 => [ Test Step 7 - Test Left Rear WSS Signal Circuit for an Open ]

Test Step 7 - Test Left Rear WSS Signal Circuit for an Open






• Connect a jumper wire between ground and the left rear WSS signal circuit in the anti lock brakes module harness connector.

• Using a 12 volt test lamp connected to 12 volts, probe the left rear WSS signal circuit.

Does the test lamp illuminate brightly?

Yes

• Go to Test Step 8 => [ Test Step 8 - Test Left Rear WSS Signal Circuit Short to Voltage ]

No

• Repair the left rear WSS signal circuit for an open.

• Perform ABS Verification Test. Refer to => Non-DTC
Based Diagnostics. ABS Verification Test

Test Step 8 - Test Left Rear WSS Signal Circuit Short to Voltage






• Turn the ignition ON.

• Remove all jumper wires.

• Measure the voltage between the left rear WSS signal circuit and ground.

Is the voltage more than one volt?

Yes

• Repair the left rear WSS signal circuit for a short to voltage.

• Perform ABS Verification Test. Refer to => Non-DTC
Based Diagnostics. ABS Verification Test

No

• Go to Test Step 9 => [ Test Step 9 - Test Left Rear WSS Signal Circuit and Left Rear WSS
12 Volt Supply Circuit Shorted Together ]

Test Step 9 - Test Left Rear WSS Signal Circuit and Left Rear WSS 12 Volt Supply Circuit Shorted Together






• Turn the ignition OFF.

• Measure the resistance between the left rear WSS signal circuit and the left rear WSS supply circuit.

Is the resistance more than 5.0 ohms?

Yes

• Go to Test Step 10 => [ Test Step 10 - Left Rear Wheel Speed Sensor ]

No

• Repair the left rear WSS signal circuit and the left rear WSS supply circuit for a short together.

• Perform ABS Verification Test. Refer to => Non-DTC
Based Diagnostics. ABS Verification Test

Test Step 10 - Left Rear Wheel Speed Sensor

• Replace the left rear wheel speed sensor.

• Perform ABS Verification Test. Refer to => Non-DTC
Based Diagnostics. ABS Verification Test


Ensure brake capability is available before road testing.

• Road test the vehicle over 40 km/h (25 m.p.h.).

• Vehicle must be driven more than 40 km/h (25 m.p.h.) for set conditions to be meet.

• With the scan tool, read ABS DTCs.

Did DTC C1020 - Left Rear Wheel Speed Sensor Circuit reset?

Yes

• Replace the anti lock brakes module.

• Perform ABS Verification Test. Refer to => Non-DTC
Based Diagnostics. ABS Verification Test

No

• Test Complete.