MIL Circuit Troubleshooting

1.Turn the ignition switch OFF.

2.Turn the ignition switch ON (II), and watch the MIL.

Does the MIL stay off?


YES - Go to 17.


NO - Go to 3.


3.Turn the ignition switch OFF.

4.Turn the ignition switch ON (II), and wait 20 seconds, and watch the MIL.

Does the MIL stay on or flash?


YES - Go to 5.


NO - The MIL circuit is OK.n


5.Turn the ignition switch OFF.

6.Connect the HDS.

7.Turn the ignition switch ON (II), and read the HDS.

Does the HDS communicate with the ECM?


YES - Go to 8.


NO - Go to ‘‘DLC Circuit Troubleshooting''.


8.Check for Temporary DTCs or DTCs in the DTCs MENU with the HDS.

Are any Temporary DTCs or DTCs indicated?


YES - If any Temporary DTCs or DTCs are indicated, go to the indicated DTC troubleshooting.n


NO - Go to 9.

9.Check the MIL in the DATA LIST with the HDS.

Does it ON indicated?


YES - Go to 12.


NO - Substitute a known-good gauge assembly, and recheck. When the MIL circuit is OK, replace the original gauge assembly.n


10.Check the SCS in the DATA LIST with the HDS.

Is it ON display?


YES - Go to 12.


NO - Substitute a known-good ECM and recheck. If symptom/indication goes away, replace the original  ECM.n


11.Turn the ignition switch OFF, and wait 10 seconds.

12.Connect the ECM test harness and the test pin box to the wire harness only, not to the ECM.

13.Disconnect the HDS.

14.Check for continuity between test pin box terminal No. 113 and body ground.

Is there continuity?


YES - Repair short in the wire between the ECM connector No. 4 terminal No. 32 (test pin box terminal No. 113) and the service check connector.n


NO - Go to 15.

15.Disconnect the gauge assembly 30P connector.

16.Check for continuity between test pin box terminal No. 91 and body ground.

Is there continuity?


YES - Repair short in the wire between the ECM connector No. 4 terminal No. 10 (test pin box terminal No. 91) and the gauge assembly.n


NO - Substitute a known-good ECM and recheck. If symptom/indication goes away, replace the original  ECM.n


17.Try to start the engine.

Does the engine start?


YES - Go to 18.


NO - Go to 23.


18.Turn the ignition switch OFF.

19.Check the No. 16 (7.5A) fuse in the under-dash fuse/relay box.

Is the fuse OK?


YES - Check for an open in the wire between the gauge assembly and the No. 16 (7.5A) fuse, if the wire is OK, go to 20.


NO - Repair short in the wire between the gauge assembly and the No. 16 (7.5A) fuse.n


20.Connect the ECM test harness and the test pin box to the wire harness only, not to the ECM.

21.Connect the test pin box terminal No. 91 to body ground with a jumper wire.

22.Turn the ignition switch ON (II).

Does the MIL come on?


YES - Substitute a known-good ECM and recheck. If symptom/indication goes away, replace the original  ECM.n


NO - Repair open in the wire between the ECM connector No. 4 terminal No. 10 (test pin box terminal No. 91) and the gauge assembly.n


23.Turn the ignition switch OFF.

24.Check the No. 11 (15A) fuse in the under-dash fuse/relay box.

Is the fuse OK?


YES - Go to 25.


NO - Go to 33.


25.Connect the ECM test harness and the test pin box to the wire harness only, not to the ECM.

26.Disconnect the inertia switch 3P connector.

27.Connect the inertia switch 3P connector terminals No. 1 and No. 3 with a jumper wire.

 

28.Turn the ignition switch ON (II).

29.Measure voltage between test pin box terminal No. 108 and body ground.

Is there battery voltage?


YES - Replace the  inertia switch.n


NO - Go to 30.

30.Turn the ignition switch OFF.

31.Remove the jumper wire from inertia switch 3P connector.

32.Check for continuity between test pin box terminal No. 108 and the inertia switch 3P connector terminals No. 3.

 

Is there continuity?


YES - Repair open in the wire between the inertia switch and the No. 11 (15A) fuse.n


NO - Repair open in the wire between the ECM connector No. 4 terminal No. 27 (test pin box terminal No. 108) and the inertia switch.n


33.Remove the driver's side under cover.

34.Remove the relay holder (A) from the under-dash fuse/relay box, and remove the PGM-FI main relay 2 (blue) (B) from the relay holder (A).

 

35.Connect the ECM test harness and the test pin box to the wire harness only, not to the ECM.

36.Check for continuity between test pin box terminal No. 108 and body ground.

Is there continuity?


YES - Repair short in the wire between the ECM connector No. 4 terminal No. 27 (test pin box terminal No. 108) and No. 11 (15A) fuse, PGM-FI main relay 2.n


NO - Go to 37.


37.Check for continuity between test pin box terminals No. 4, No. 5, No. 98, No. 120 and body ground individually.

Is there continuity?


YES - Check for an open in the wire between the PGM-FI main relay 1 and ECM connector No. 4 terminal No. 11 (test pin box terminal No. 92), if wire is OK, then go to fuel pump circuit troubleshooting.n


NO - Repair open in the wire between the ECM connector No. 1 terminal No. 4 (test pin box terminal No. 4), ECM connector No. 1 terminal No. 5 (test pin box terminal No. 5), ECM connector No. 4 terminal No. 17 (test pin box terminal No. 98), ECM connector No. 4 terminal No. 39 (test pin box terminal No. 120) and G102.n