P0501

P0501-VEHICLE SPEED SENSOR 1 PERFORMANCE





For a complete wiring diagram refer to the Wiring Information Electrical Diagrams.

- When Monitored:
While the engine is running.

- Set Condition:
The ECM indicates signals of motion; however, the VSS does not.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure

1. DTC IS ACTIVE
1. Turn the ignition on.
2. With the scan tool, clear DTCs.
3. Turn the ignition off.
4. Turn the ignition on.
5. With the scan tool, select View DTCs.

Is the status Active for this DTC?

Yes

- Go To 2

No

- Go To 15

2. WHEEL SPEED SENSOR INSPECTION
1. Turn the ignition off.
2. Inspect the Wheel Speed Sensor for proper mounting.
3. Inspect the Wheel Speed Sensor harness and connector.
4. Inspect the Wheel Speed Sensor for excessive debris on the sensor.

Were any problems found?

Yes

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

No

- Go To 3

3. TONE WHEEL DAMAGED/MISSING
1. Inspect the Tone Wheel.

NOTE: The Tone Wheel Teeth should be perfectly square, not bent or nicked.

Were any problems found?

Yes

- Replace the Tone Wheel.
- Perform ABS VERIFICATION TEST. ABS Verification Test

No

- Go To 4

4. EXCESSIVE WHEEL SPEED SENSOR AIR GAP
1. Measure the Wheel Speed Sensor Air Gap.

Were any problems found?

Yes

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

No

- Go To 5

5. WHEEL BEARING LOOSE/BINDING
1. Inspect the wheel bearings for excessive run out or improper clearance.

Were any problems found?

Yes

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

No

- Go To 6

6. (B222) REAR WHEEL SPEED SENSOR SUPPLY CIRCUIT SHORTED TO GROUND




1. Turn the ignition off.
2. Disconnect the Rear Wheel Speed Sensor harness connector.
3. Disconnect the Anti-lock Brake Module harness connector.

NOTE: Check connector - Clean/repair as necessary.

4. Measure the resistance between the (B222) Rear Wheel Speed Sensor Supply circuit and ground.

Is the resistance above 5.0 ohms?

Yes

- Go To 7

No

- Repair the (B222) Rear Wheel Speed Sensor Supply circuit for a short to ground.
- Perform ABS VERIFICATION TEST. ABS Verification Test

7. (B22) REAR WHEEL SPEED SENSOR SIGNAL CIRCUIT SHORTED TO GROUND




1. Measure the resistance between the (B22) Rear Wheel Speed Sensor Signal circuit and ground.

Is the resistance above 5.0 ohms?

Yes

- Go To 8

No

- Repair the (B22) Rear Wheel Speed Sensor Signal circuit for a short to ground.
- Perform ABS VERIFICATION TEST. ABS Verification Test

8. (B222) REAR WHEEL SPEED SENSOR SUPPLY CIRCUIT OPEN




1. Measure the resistance of the (B222) Rear Wheel Speed Sensor Supply circuit.

Is the resistance below 5.0 ohms?

Yes

- Go To 9

No

- Repair the open (B222) Rear Wheel Speed Sensor Supply circuit.
- Perform ABS VERIFICATION TEST. ABS Verification Test

9. (B22) REAR WHEEL SPEED SENSOR SIGNAL CIRCUIT OPEN




1. Measure the resistance of the (B22) Rear Wheel Speed Sensor Signal circuit.

Is the resistance below 5.0 ohms?

Yes

- Go To 10

No

- Repair the open (B22) Rear Wheel Speed Sensor Signal circuit.
- Perform ABS VERIFICATION TEST. ABS Verification Test

10. (B222) REAR WHEEL SPEED SENSOR SUPPLY CIRCUIT SHORTED TO VOLTAGE




1. Turn the ignition on.
2. Measure the voltage of the (B222) Rear Wheel Speed Sensor Supply circuit.

Is there any voltage present?

Yes

- Repair (B222) Rear Wheel Speed Sensor Supply circuit for a short to voltage.
- Perform ABS VERIFICATION TEST. ABS Verification Test

No

- Go To 11

11. (B22) REAR WHEEL SPEED SENSOR SIGNAL CIRCUIT SHORTED TO VOLTAGE




1. Measure the voltage of the (B22) Rear Wheel Speed Sensor Signal circuit.

Is there any voltage present?

Yes

- Repair the (B22) Rear Wheel Speed Sensor Signal circuit for a short to voltage.
- Perform ABS VERIFICATION TEST. ABS Verification Test

No

- Go To 12

12. (B222) REAR WHEEL SPEED SENSOR SUPPLY CIRCUIT SHORTED TO THE (B22) REAR WHEEL SPEED SENSOR SIGNAL CIRCUIT




1. Turn the ignition off.
2. Measure the resistance between the (B222) Rear Wheel Speed Sensor Supply circuit and the (B22) Rear Wheel Speed Sensor Signal circuit at the Anti-lock Brake Module harness connector.

Is the resistance below 5.0 ohms?

Yes

- Repair (B222) Rear Wheel Speed Sensor Supply circuit for a short to the (B22) Rear Wheel Speed Sensor Signal circuit.
- Perform ABS VERIFICATION TEST. ABS Verification Test

No

- Go To 13

13. REAR WHEEL SPEED SENSOR




1. Turn the ignition off.
2. Connect the Rear Wheel Speed Sensor harness connector.
3. Measure the resistance between the (B222) Rear Wheel Speed Sensor Supply circuit and (B22) Rear Wheel Speed Sensor Signal circuit at the Anti-lock Brake Module harness connector.

NOTE: The resistance should be approximately 1600-2300 ohms at 76° F (24.5° C).

Is the resistance within the noted range?

Yes

- Go to 14

No

- Replace the Rear Wheel Speed Sensor.
- Perform ABS VERIFICATION TEST. ABS Verification Test

14. ANTI-LOCK BRAKE MODULE
1. Turn the ignition off.
2. Inspect the related wiring harness. Look for any chafed, pierced, pinched, or partially broken wires.
3. Inspect the related wire harness connectors. Look for broken, bent, pushed out, or corroded terminals.
4. Search for any Technical Service Bulletins that may apply.

Were any problems found?

Yes

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

No

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

15. WIRING HARNESS INSPECTION
1. Turn the ignition off.

NOTE: Towing the vehicle with ignition ON may set this DTC.

2. Inspect the related wiring harness. Look for any chafed, pierced, pinched, or partially broken wires.
3. Inspect the related wire harness connectors. Look for broken, bent, pushed out, or corroded terminals.
4. Search for any Technical Service Bulletins that may apply.

Were any problems found?

Yes

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

No

- Test Complete.