Engine Control Module: Service and Repair

ECM/PCM PROBLEM INSPECTION PROCEDURE

1. TEST ECM/PCM GROUND CIRCUIT: Measure resistance between ECM/PCM and chassis ground using the backside of ECM/PCM harness connector as ECM/PCM side check point. If the problem is found, repair it.

Specification (Resistance): 1Ohms or less

2. TEST ECM/PCM CONNECTOR: Disconnect the ECM/PCM connector and visually check the ground terminal on ECM/PCM side and harness side for bent pins or poor contact pressure, If the problem is found, repair it.
3. If problem is not found in Step 1 and 2, the ECM/PCM could be faulty. If so, replace the ECM/PCM with a new one, and then check the vehicle again. If the vehicle operates normally then the problem was likely with the ECM/PCM.
4. RE-TEST THE ORIGINAL ECM/PCM : Install the original ECM/PCM (may be broken) into a known-good vehicle and check the vehicle. If the problem occurs again, replace the original ECM/PCM with a new one. If problem dose not occur, this is intermittent problem .