C1027

C1O27-LEFT REAR WHEEL SPEED SENSOR SIGNAL ERRATIC PERFORMANCE






When Monitored:

With the ignition on

Set Condition:

When the Left Rear Wheel Speed Signal circuit indicates continuously too high or too low wheel speed





Diagnostic Test

1. CHECK FOR A DTC C1011-LEFT FRONT WHEEL SPEED SENSOR SIGNAL ERRATIC PERFORMANCE





NOTE: This DTC must be active for the results of this test to be valid

Turn the ignition on

With the scan tool read and record DTCs

With the scan tool read and record Freeze Fame information

With the scan tool erase DTCs

CAUTION: Ensure braking capability is available before road testing

Drive the vehicle over 25 km/h (15 mph)

Park the vehicle and cycle the ignition switch from off to on

With the scan tool read and record DTC's

Does the scan tool display: C1011-LEFT FRONT WHEEL SPEED SENSOR SIGNAL ERRATIC PERFORMANCE?

Yes

- Go To 2

No

- Refer to the INTERMITTENT CONDITION diagnostic procedure. Testing and Inspection
- Perform ABS VERIFICATION TEST VER 1. ABS Verification Test

2. CHECK THE TERMINALS/CONNECTORS/TONE WHEEL FOR DAMAGE





NOTE: Check all related wiring for bruised chafed pierced, or partially broken wires

NOTE: Check all related connectors for broken, bent, pushed out, or corroded terminals

NOTE: Check the tone wheel teeth for missing teeth, cracks, or looseness Teeth should be perfectly square, not bent, or nicked

Turn the ignition off

Visually inspect the Anti-Lock Brake Module harness connector Left REAR WSS Left REAR WSS harness connector and Left REAR WSS tone wheel (if applicable) for damage

Were any problems found?

Yes

- Repair as necessary
- Perform ABS VERIFICATION TEST VER 1. ABS Verification Test

No

- Go To 3

3. CHECK THE (B3) LEFT REAR WSS SIGNAL AND THE (B4) LEFT REAR WSS SUPPLY CIRCUITS FOR A SHORT TOGETHER





Turn the ignition off

Disconnect the Anti-Lock Brake Module harness connector Disconnect the Left REAR WSS harness connector Measure the resistance between the (B3) Left REAR WSS Signal and the (B4) Left REAR WSS Supply circuits at the Left REAR WSS harness connector

Is the resistance above 5.O ohms?

Yes

- Go To 4

No

- Repair the (B3) Left REAR WSS Signal and the (B4) Left REAR WSS Supply circuits for a short together
- Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test

4. CHECK THE VOLTAGE ON THE (B4) LEFT REAR WSS SUPPLY CIRCUIT





Turn the ignition off.

Reconnect the Anti-Lock Brake Module harness connector.

Disconnect the Left REAR WSS harness connector.

Turn the ignition on.

Measure the voltage of the (B4) Left REAR WSS Supply circuit in the Left REAR WSS harness connector.

Is the voltage above 10 volts?

Yes

- Go To 8

No

- Go To 5

5. CHECK THE (B4) LEFT REAR WSS SUPPLY CIRCUIT FOR A SHORT TO GROUND





Turn the ignition off.

Disconnect the Anti-Lock Brake Module harness connector.

Disconnect the Left REAR WSS harness connector.

Using a 12-volt test light connected to 12-volts check the (B4) Left REAR WSS Supply circuit.

Does the test light illuminate brightly?

Yes

- epair the (B4) Left REAR WSS Supply circuit for a short to ground.
- Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test.

No

- Go To 6

6. CHECK THE (B4) LEFT REAR WSS SUPPLY CIRCUIT FOR A SHORT TO VOLTAGE





Turn the ignition off.

Disconnect the Anti-Lock Brake Module harness connector.

Disconnect the Left REAR WSS harness connector.

Using a 12 volt test light connected to ground check 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 voltage.
- Perform ABS VERIFICATION TEST VER 1. ABS Verification Test.

No

- Go To 7

7. CHECK THE (B4) LEFT REAR WSS SUPPLY CIRCUIT FOR AN OPEN





Turn the ignition off.

Disconnect the Anti-Lock Brake Module harness connector.

Disconnect the Left REAR WSS harness connector.

Connect a jumper wire between the (B4) Left REAR WSS Supply circuit and ground.

Using a 12-volt test light connected to 12-volts check the (B4) Left REAR WSS Supply circuit.

Does the test light illuminate brightly

Yes

- Replace the Anti-Lock Brake Module
- Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test.

No

- Repair the (B4) Left REAR WSS Supply circuit for an open.
- Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test.

8. CHECK THE (B4) LEFT REAR WSS SUPPLY AND THE (B3) LEFT REAR WSS SIGNAL VOLTAGE





Turn the ignition off.

Disconnect the Left REAR WSS harness connector.

Turn the ignition on.

Measure the voltage between the (B4) Left REAR WSS Supply and (B3) Left REAR WSS Signal circuits at the Left REAR WSS harness connector.

Is the voltage above 10 volts?

Yes

- Go To 12

No

- o To 9

9. CHECK THE (B3) LEFT REAR WSS SIGNAL CIRCUIT FOR A SHORT TO GROUND





Turn the ignition off.

Disconnect the Anti-Lock Brake Module harness connector.

Disconnect the Left REAR WSS harness connector.

Using a 12-volt test light connected to 12-volts check 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. ABS Verification Test.

No

- Go To 10

10. CHECK THE (B3) LEFT REAR WSS SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE





Turn the ignition off.

Disconnect the Anti-Lock Brake Module harness connector.

Disconnect the Left REAR WSS harness connector.

Using a 12 volt test light connected to ground check 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 voltage.
- Perform ABS VERIFICATION TEST VER 1. ABS Verification Test.

No

- Go To 11

11. CHECK THE (B3) LEFT REAR WSS SIGNAL CIRCUIT FOR AN OPEN





Turn the ignition off.

Disconnect the Anti-Lock Brake Module harness connector.

Disconnect the Left REAR WSS harness connector.

Connect a jumper wire between the (B3) Left REAR WSS Signal circuit and ground.

Using a 12-volt test light connected to 12-volts check the (B3) Left REAR WSS Signal circuit.

Does the test light illuminate brightly?

Yes

- Replace the Anti-Lock Brake Module
- Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test.

No

- Repair the (B3) Left REAR WSS Signal circuit for an open.
- Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test.

12. CHECK THE (B3) LEFT REAR WSS SIGNAL CIRCUIT FOR A SHORT TO GROUND





Turn the ignition off.

Disconnect the Anti-Lock Brake Module harness connector.

Disconnect the Left REAR WSS harness connector.

Using a 12-volt test light connected to 12 wolts, check 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. ABS Verification Test.

No

- Go To 13

13. CHECK THE (B3) LEFT REAR WSS SIGNAL VOLTAGE AT THE LEFT REAR WSS HARNESS CONNECTOR





Turn the ignition off.

Reconnect all connectors.

Turn the ignition on.

While back probing measure between the (B3) Left REAR WSS Signal circuit and chassis ground at the Left REAR WSS harness connector.

Slowly rotate the wheel by hand.

Did the (B3) Left REAR WSS Signal circuit voltage toggle between approximately 1.6 to 8 volts?

Yes

- Go To 14

No

- Replace the Left REAR WSS
- Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test.

14. CHECK THE (B3) LEFT REAR WSS SIGNAL VOLTAGE AT THE ANTILOCK BRAKE MODULE HARNESS CONNECTOR





Turn the ignition off Turn the ignition on

While back probing measure between the (B3) Left REAR WSS Signal circuit and chassis ground at the AntiLock Brake Module harness connector

Slowly rotate the wheel by hand

Did the (B3) Left REAR WSS Signal circuit voltage toggle between approximately 1.6 to 8 volts?

Yes

- Replace the Anti-Lock Brake Module
- Perform ABS VERIFICATION TEST VER 1. ABS Verification Test

No

- Repair the (B3) Left REAR WSS Signal circuit for an open
- Perform ABS VERIFICATION TEST VER 1. ABS Verification Test