DTC P0503 - Vehicle Speed Sensor
1) Continuous Memory P0503: Check For Intermittent Fault This code indicates poor VSS performance. Possible causes for this code are:
- Noisy VSS input signal from RFI/EMI external source (ignition wires, charging circuits etc.).
- Damaged circuit.
- Faulty VSS.
- Faulty VSS gear(s).
Turn ignition off. Disconnect VSS sensor. Visually inspect VSS and VSS circuits for potential faults as follows:
- Loose VSS circuit connectors.
- Loose VSS circuit connector pins.
- Damaged VSS wiring harness insulation.
- Incorrect VSS circuit routing.
- Incorrect VSS installation.
If no faults are found, go to next step. If faults are found, repair or replace as necessary. Clear PCM memory and go to step 5).
2) Check PCM VSS PID For Input Signal Turn ignition off. Connect scan tool to DLC. Test drive vehicle, averaging 30 MPH. While driving at a steady speed, check for VSS PID variations of more than 5 MPH for 10 seconds or more. If any variations occur, go to next step. If variations do not occur, fault cannot be duplicated at this time. Testing is complete.
3) Visually inspect VSS wiring harness. Ensure wiring is not routed near ignition wires or generator wires. Verify VSS wiring harness is shielded and grounded (if applicable). Repeat step 1) to verify circuit continuity. If faults are found, repair or replace as necessary. Clear PCM memory and go to step 5). If no faults are found, fault cannot be duplicated at this time. Testing is complete.
4) VSS Drive Cycle Record and clear continuous memory codes. Warm engine to normal operating temperature. Perform appropriate drive cycle as follows:
- On models with A/T, place gear selector in Drive position. Accelerate hard to 35 MPH and coast down to a stop. Repeat procedure 3 times. Shut off engine. Repeat QUICK TEST. Service codes as necessary. If no codes are present, testing is complete.
- On models with M/T, start in first gear, shifting no higher than second gear. Accelerate moderately to 40 MPH. Coast down to idle, and stop. Repeat procedure 3 times. Shut engine off. Repeat QUICK TEST. Service codes as necessary. If no codes are present, testing is complete.
5) VSS Drive Cycle Record and clear continuous memory codes. Warm engine to normal operating temperature. Perform appropriate drive cycle as follows:
- On models with A/T, place gear selector in Drive. Accelerate hard to 35 MPH and coast down to a stop. Repeat procedure 3 times. Shut off engine. Repeat QUICK TEST. Service codes as necessary. If no codes are present, testing is complete.
- On models with M/T, start in first gear, shifting no higher than second gear. Accelerate moderately to 40 MPH. Coast down to idle, and stop. Repeat procedure 3 times. Shut engine off. Repeat QUICK TEST. Service codes as necessary. If no codes are present, testing is complete.