With Throttle Body Injection (TBI)

Fig. 026 - Wiring Diagram for Chart A-1 No "Service Engine Soon" Light. VIN K, VIN R, VIN U:

CHART A-1

WON'T FLASH CODE 12

NO "SERVICE ENGINE SOON" LIGHT

2.5L "A & N" SERIES

2.0L OHC (VIN K) "J" SERIES

FUEL INJECTION (TBI)

Circuit Description:
There should always be a steady "Service Engine Soon" light, when the ignition is "ON" and engine stopped. Battery 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 CKT 419 to the ECM.

Fig. 025 Chart A-1 - No "Service Engine Soon" Light:

Test Description:
Step numbers refer to step numbers on diagnostic chart.
1. Battery feed CKT 240 is protected by a fusible link at the battery.
2. Using a test light connected to 12 volts, probe each of the system ground circuits to be sure a good ground is present. See ECM terminal end view in front of this section for ECM pin locations of ground circuits.




Diagnostic Aids:
Engine runs OK, check:
a. Faulty light bulb
b. CKT 419 open
c. Gage fuse blown. This will results in no stop lights, oil, or generator lights, seat belt reminder, etc.

Engine cranks, but will not run.
a. Continuous battery - fuse or fusible link open
b. ECM ignition fuse open
c. Battery CKT 240 to ECM open
d. Ignition CKT 439 to ECM open
e. Poor connection to ECM