DTC P0500: No Vehicle Speed Sensor Signal: Testing

NOTE: Any VSS DTCs in the Controller Anti-Lock Brake Module or Body Controller must be properly diagnosed before continuing. See appropriate ANTI-LOCK article in BRAKES or appropriate BODY CONTROL MODULES article in ACCESSORIES & EQUIPMENT.

Turn ignition on, engine not running. With the DRBIII®, read DTCs. Is the Good Trip counter displayed and equal to zero? If yes, go to next step. If no, go to INTERMITTENT CONDITION under SELF-DIAGNOSTIC SYSTEM.
Turn the ignition off. Disconnect the PCM harness connectors. Disconnect the Controller Anti-Lock Brake (CAB) module harness connector. Measure the resistance of the Vehicle Speed Signal circuit between the PCM harness connector and the CAB harness connector. Is the resistance above 5.0 ohms? If yes, repair the open Vehicle Speed Signal circuit. If no, go to next step.
Measure the resistance between ground and the Vehicle Speed Signal circuit at the PCM harness connector. Is the resistance below 100 ohms? If yes, repair the Vehicle Speed Signal circuit for a short to ground. If no, go to next step.
Turn the ignition off. Reconnect the CAB harness connector. Turn ignition on, engine not running. Measure the voltage on the (G7) Vehicle Speed Signal circuit at the PCM harness connector. Is the voltage above 4.8 volts? If yes, repair the Vehicle Speed Signal circuit short to voltage. If no, go to next step.

NOTE: Before continuing, check the PCM harness connectors for corrosion, damage, or terminal push out. Repair as necessary.

Using the wiring diagram as a guide, inspect the wire harness and connectors. Pay particular attention to all power and ground circuits. If there are no possible causes remaining, replace PCM. Program the new PCM. See PROGRAMMING .