Chart A-1 No Malfunction Indicator Lamp (MIL)

Chart A-1:

Malfunction Indicator Lamp (MIL) Service Engine Soon Schematic:

CIRCUIT DESCRIPTION
There should always be a steady Malfunction Indicator Lamp (MIL) (Service Engine Soon) when the ignition is "ON" and engine stopped. Ignition is supplied directly to the light bulb. The Powertrain Control Module (PCM) will turn the MIL "ON" by grounding CKT 419 at the PCM.

CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.

1. With CKT 419 jumpered directly to ground, the MIL (Service Engine Soon) should be "ON." If not, CKT 419 or CKT 39 is open, or the bulb or cluster is bad.
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 "PCM Connector Views" for PCM pin locations of ground circuits.

DIAGNOSTIC AIDS
Engine runs OK, check:
^ Faulty light bulb.
^ CKT 419 open or CKT 39 open.
^ 10 amp gauges fuse open.

Engine cranks, but will not run:
^ 15 amp fuel pump in-line fuse holder or fusible link open
^ Ignition CKT 439 to PCM open.
^ PCM ignition fuse.
^ Poor connection to PCM.