ECM Ground Circuit Check

- First check the ECU ground circuit.
- If it is faulty, repair it.
- If it is normal, the ECU could be faulty, so replace the ECU with a known good one and check if the symptoms appear.





- Measure the resistance between the ECU ground terminal and the body ground.

Resistance: 1 Ohm or less





- Disconnect the ECU connector, check the ground terminals on the ECU side and the wire harness side for bend and check the contact pressure.