Component Tests and General Diagnostics

ECM problem inspection procedure

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

Specification (Resistance)
Between terminal 1 of C230-1 connector and chassis ground : 1Ohms or less
Between terminal 2 of C230-1 connector and chassis ground : 1Ohms or less


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