MIL Circuit Troubleshooting

1.Turn the ignition switch ON (II).

2.Do the gauge self-diagnostic function.

Does the MIL indicator flash?


YES - Go to 3.


NO - Substitute a known-good gauge control module (tach), and recheck. If the MIL circuit is OK, replace the original gauge control module (tachometer).n


3.Connect the HDS to the DLC.

4.Check the SCS in the DATA LIST with the HDS.

Is a short indicated?


YES - Go to 5.


NO - Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM.n


5.Turn the ignition switch OFF.

6.Disconnect ECM connector A (44P), then disconnect the HDS.

7.Check for continuity between ECM connector terminal A31 and body ground.

 

Is there continuity?


YES - Repair short in the wire between the ECM (A31), the SRS unit, and the DLC.n


NO - Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck. If the symptom/indication goes away with a known-good ECM, replace the original ECM.n