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Home >> Isuzu >> 1996 >> Trooper LS, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Basic Testing >> Trouble Shooting >> No Malfunction Indicator Light
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No Malfunction Indicator Light

  1. Perform On-Board Diagnostic (OBD) System Check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  . After performing OBD system check, go to next step.
  2. Attempt to start engine. If engine does not start, go to step 6). If engine starts, go to next step.
  3. Check METER GAUGE fuse C-10 (10-amp) located in dash fuse box. If fuse is okay, go to next step. If fuse is blown, go to step 16).
  4. Turn ignition on. Using test light connected to ground, probe ignition feed circuit at instrument cluster terminal No. 14 (Blue/Yellow wire). If test light illuminates, go to next step. If test light does not illuminate, go to step 13).
  5. Turn ignition off. Disconnect PCM C-1 electrical connector. Connect a jumper wire between ground and MIL control circuit at PCM connector C-1 terminal A13 (Violet wire). Turn ignition on. If MIL comes on, go to step 10). If MIL does not come on, go to step 11).
  6. Check ENGINE fuse C-8 (15-amp) located in dash fuse box. Check PCM fuse FL-3 (30-amp) in fuse/relay box located in engine compartment. If fuses are okay, go to next step. If fuses are blown, go to step 15).
  7. Turn ignition off. Disconnect PCM C-3 electrical connector. Turn ignition on. Using test light connected to ground, probe ignition feed circuits at PCM connector C-3 terminal E16 and F16 (Red/Blue wires). If test light illuminates, go to next step. If test light does not illuminate, go to step 12).
  8. Using test light connected to ground, probe battery feed circuit at PCM connector C-1 terminal A4 (Red/White wire). If test light illuminates, go to next step. If test light does not illuminate, go to step 14).
  9. Check for faulty PCM ground connections. Repair as necessary. If connections are okay, go to next step.
  10. Check PCM connectors for damaged terminals. If any terminals are damaged, replace PCM. If PCM connector terminals are okay, go to step 17).
  11. Check for an open in MIL control circuit (Violet wire) between PCM and MIL. Repair as necessary. If circuit is okay, go to step 18).
  12. Substitute PCM main relay with a known good relay. PCM main relay is located in fuse/relay box in engine compartment. Observe MIL. If MIL operates properly, replace PCM main relay. If MIL still does not operate, go to next step.
  13. Repair open in ignition feed circuit (Black/Yellow wire) between PCM main relay and dash fuse box.
  14. Repair open in PCM battery feed circuit (Red/White wire) between PCM and fuse/relay box located in engine compartment.
  15. Repair short to ground in PCM ignition feed circuit (Black/Yellow or Red/Blue wire) or PCM battery feed circuit (Red/White wire). See appropriate wiring diagram in WIRING DIAGRAMS  section. Replace fuse.
  16. Repair the short to ground in ignition feed circuit (Blue/Yellow wire) between instrument cluster and dash fuse box. Replace fuse.
  17. Replace PCM. Verify proper system operation.
  18. Check MIL driver circuit (Violet wire) for poor connection at instrument cluster connector. Repair as necessary. If no problem is found, diagnose problem in instrument cluster.
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