No Malfunction Indicator Lamp (MIL)

Diagnostic Chart:

Schematic Diagram:

CHART III

NO MALFUNCTION INDICATOR LAMP
There should always be a steady malfunction indicator lamp illuminated when the ignition is On and engine stopped. Battery voltage is supplied directly to the bulb. The powertrain control module (PCM) will control the lamp and turn it On by providing a ground path through circuit 419 to the PCM.

PARAMETERS
Lamp will not illuminate if power or ground is lost to the PCM or bulb.

Lamp will not illuminate if bulb is shorted or open.

DIAGNOSTIC AIDS:
Engine runs OK, check:
^ Faulty bulb.
^ Circuit 419 open.
^ Ignition 1 fuse blown.
^ Faulty Quad driver.

Engine cranks but will not run:
^ PCM B fuse blown.
^ PCM 1 fuse blown.
^ Ignition 4 Maxi fuse blown.
^ Circuits 1140 or 439 open.
^ Terminal tightness at PCM.

PCM Grounds
^ Circuits 551 and 451 from J1C02 and J1CO1.