Malfunction Indicator Lamp Inoperative

DIAGNOSTIC CHART





WIRING DIAGRAM

INSPECTION PROCEDURE

Circuit Description:
There should always be a steady "Check Engine" MIL, when the ignition is "ON" and engine stopped.
Ignition voltage is supplied directly to the light bulb. The Engine Control Module (ECM) will control the light and turn it "ON" by providing a ground path through CKT 03 to the ECM.

Test Description:
Number(s) below refer to circled number(s) on the diagnostic chart.
1. Battery feed CKTs Ci6 and B1 are protected by a 60 amp main-1 fuse. Located at fuse and relay convenience center. (Engine compartment R. H. side). If this fuse was open, refer to CHASSIS ELECTRICAL.
2. Using a test light connected to 12 volts, probe each of the system ground circuits to be sure a good ground is present. Refer to "ECM Terminal End View" in front of this section for ECM pin locations of ground circuits.

Diagnostic Aids:
Engine runs OK, check:
- Faulty light bulb
- CKT A5 open
- Gauge fuse blown. This will result in no oil, or generator lights, seat belt reminder, etc.

Engine cranks, but will not start.
- Fusible link, open
- 15 amp ignition fuse (fuse box under dash L. H. side)
- 15 amp ECM fuse (fuse and relay convenience center, engine compartment R. H. side)
- 10 amp room L fuse (fuse box under dash L. H. side)
- Battery CKTs C16 and B1 to ECM open
- Ignition CKT A6 to ECM open
- Poor connection to ECM