P1501

P1501-VEHICLE SPEED SENSOR 1/2 CORRELATION - DRIVE WHEELS







- When Monitored:
Ignition on and vehicle moving. Cruise is learned and customer is trying to use the Cruise.

- Set Condition:
The PCM recognizes rear wheel speed is greater than front wheel speed. One trip fault.





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

1. DTC IS ACTIVE
1. Start the engine.
2. Allow the engine to reach normal operating temperature.

NOTE: Diagnose and repair any system voltage or sensor reference voltage DTCs before continuing with this test.

NOTE: Check for any Bus Communication DTCs. If no Bus or Communication DTCs are set, check for active Vehicle Speed Sensor DTCs in the Totally Integrated Power Module. Any bus, communication, or VSS DTCs in the TIPM must be properly diagnosed before continuing.

NOTE: This code may set after a hard acceleration on loose gravel, during other off road driving conditions, or by any condition that causes a wheel speed difference between the front and rear wheels.

NOTE: It may be necessary to test drive the vehicle within the DTC monitoring conditions in order for this DTC to set.

3. With the scan tool, select View DTCs.

Is the status Active for this DTC?

Yes

- Go to 2

No

- Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. Checking for an Intermittent DTC

2. VISUAL INSPECTION

NOTE: This code can set due to tire circumference differences and from the front or rear wheels being on a slippery surface while the opposite tires are not.

1. This code may also set on a hard acceleration on loose gravel or during other off road driving conditions.
2. Check tire pressure of all the tires.
3. Check tire wear on all the tires.
4. Ask the customer what the road and driving conditions were like when the fault set.

Were any problems found?

Yes

- Repair as necessary. If the code sets during a front OR rear wheel spin condition, no repair is necessary.
- Perform the PCM Verification Test. PCM Verification Test

No

- Go to 3

3. POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Vehicle Speed Sensor and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched, or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals.
4. Monitor the scan tool data relative to this circuit and wiggle test the wiring and connectors.
5. Look for the data to change or for the DTC to reset during the wiggle test.
6. Search for any Technical Service Bulletins that may apply.

Were any problems found?

Yes

- Repair as necessary.
- Perform the PCM Verification Test. PCM Verification Test

No

- Replace and program the Powertrain Control Module (PCM).
- Perform the PCM Verification Test. PCM Verification Test