ECM Power and Ground Supply Circuit Check

ECM Power And Ground Supply Circuit:

INSPECTION
- Disconnect the negative battery cable.
- Disconnect the ECM connectors.
- Connect the negative battery cable.
- Turn key ON.
- Check for battery voltage between ECM harness terminals:
12 and ground
21 and ground
33 and ground
- Check for continuity between ECM harness terminals:
11 and ground
20 and ground

RESULTS AND CORRECTION
- If voltage was not present at terminals 12, 21 or 33, check the following:
Main relay
Ignition switch
Fuses
Fuse links
Wiring continuity
- If continuity did not exist between terminals 11 and ground or 20 and ground check the following.
All ECM ground points
Wiring continuity
- If voltage and continuity results were satisfactory, the power and ground circuit to the ECM is OK.