Troubleshooting Flowchart Engine Control Module (ECM)
Malfunction Indicator Lamp (MIL)
never comes on (even for two se-
conds) after ignition is turned on.
Is the low oil pressure light on?
Turn the ignition switch OFF.
Connect the test harness between
the ECM and connectors (see
page 11-37).
Connect A13 terminal to body
ground.
Turn the ignition switch ON.
Is the MIL on?
Measure voltage between body
ground and the following termi-
Is there less than 1.0 V?
Substitute a known-good ECM
and recheck. If symptom/indica-
tion goes away, replace the origi-
nal ECM.
Inspect No. 5 (10 A) fuse in the
under-dash fuse box.
Is the fuse OK?
Repair open in YEL wire between
No. 5 (10 A) fuse and gauge as-
sembly.
Replace the MIL bulb.
Repair open in BLU wire be-
tween ECM (A13) and gauge
assembly.
Repair open in wire between ECM
and G101 (located at right middle
of engine) that had more than 1.0
V.
Replace the fuse.
G101
(cont’d)
nals individually: A23, A24,
A26, B2.
Malfunction Indicator Lamp (MIL)
never comes on (even for two se-
conds) after ignition is turned on.
Is the low oil pressure light on?
Turn the ignition switch OFF.
Connect the test harness between
the ECM and connectors (see
page 11-37).
Connect A13 terminal to body
ground.
Turn the ignition switch ON.
Is the MIL on?
Measure voltage between body
ground and the following termi-
Is there less than 1.0 V?
Substitute a known-good ECM
and recheck. If symptom/indica-
tion goes away, replace the origi-
nal ECM.
Inspect No. 5 (10 A) fuse in the
under-dash fuse box.
Is the fuse OK?
Repair open in YEL wire between
No. 5 (10 A) fuse and gauge as-
sembly.
Replace the MIL bulb.
Repair open in BLU wire be-
tween ECM (A13) and gauge
assembly.
Repair open in wire between ECM
and G101 (located at right middle
of engine) that had more than 1.0
V.
Replace the fuse.
G101
(cont’d)
nals individually: A23, A24,
A26, B2.