Circuit/System Testing
- Install a scan tool
- Start the engine
- With the scan tool, observe the Engine Speed parameter in the ECM/PCM Engine Data list.
- If the engine speed parameter matches the tachometer display, check for a poor connection at the harness connector of the ECM/PCM.
- Turn OFF the ignition.
- Disconnect the ECM/PCM connector C000
- With the ignition ON, install one lead of the signal generator to the engine speed signal circuit at the ECM/PCM connector and the other lead to a good ground.
- Set the signal generator to generate a tachometer signal and observe the vehicle tachometer.
- If the vehicle tachometer indicates an engine RPM, check for a poor connection at the harness connector of the ECM/PCM.
- If the connector is normal, replace the ECM/PCM.
- If the vehicle tachometer does not indicate an engine RPM, test the engine speed signal circuit for a short to voltage, short to ground or an open.
- If the engine speed circuit tests normal, replace the IPC.