A-1 ~ No Malfunction Indicator Lamp (MIL)

Chart A-1 Circuit Diagram:

Diagnostic Chart A-1 No DTC 12 / No MIL Light:

CIRCUIT DESCRIPTION:

There should always be a steady "CHECK ENGINE" light, when the ignition is "ON" and engine stopped. Battery voltage is supplied directly to the light bulb. The Electronic Control Module (ECM) will control the light and turn it "ON" by providing a ground path through the RED wire to the ECM.

TEST DESCRIPTION: Numbers below refer to circled numbers on the diagnostic chart.

1. Battery feed terminals "C16" and "B1" protected by a fusible link in relay fuse center under the hood near the battery.

2. If terminals "C16" and "B1" have voltage, the ECM grounds or the ECM are faulty.

3. Using a test light connected to 12 volts, prove each of the system ground circuits to be sure a good ground is present.

DIAGNOSTIC AIDS:

Engine runs OK, check:

^ Faulty light bulb.
^ RED wire open.
^ Meter fuse (10 amp) blown. This will result in no oil or generator lights, seat belt reminder, etc.

Engine cranks, but will not run:

^ Continuous battery fuse or fusible link open.
^ ECM ignition fuse open.
^ Battery RED/WHITE wire to ECM open.
^ Ignition RED/GRN wire to ECM open.
^ Poor connection to ECM.