MIL Circuit Troubleshooting

LED CHECK

If a system problem is detected, both dash warning light and LED on ECU will light. When ignition is turned "OFF" and back "ON," dash light should only light for about 2 seconds, then go out, unless a problem is again detected. LED on ECU will remain lit until problem is corrected and memory is erased. If, after switching ignition "OFF" and back "ON," LED does not light, check for:

1. Blown Hazard fuse (10A).
2. Open circuit in white/yellow wire between ECU terminal A17 and Hazard fuse.
3. If no problem is detected, install known good ECU and recheck.

WARNING LIGHT CHECK

If, after switching ignition "OFF" and back "ON," dash warning light does not illuminate, check for:

1. Blown #5 fuse (also for back-up lights, seat belt alarm, and clock).
2. Open circuit in yellow wire between #5 fuse and combination meter.
3. Open circuit in green/red wire between combination meter and ECU terminal B6.
4. Open circuit in black wires between ECU terminals A2, A4, and ground 1.
5. Burned out warning light bulb.
6. If no problem is detected, install known good ECU and recheck.