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HOMESERVICE MANUALSOLDSMOBILE1998ACHIEVA 3.1 M, 4T40E/MN4REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT VARIANT/TRIMSECTION 1 (ENGINE CONTROLS - TESTS W/CODES - 2.4L)SELF-DIAGNOSTIC SYSTEMMIL INOPERATIVE
1998 Oldsmobile Achieva 3.1 M, 4T40E/MN4

Mil Inoperative

1998 Oldsmobile Achieva 3.1 M, 4T40E/MN4SECTION Mil Inoperative
WARNING: This page is about a different variant/trim than selected.
  1. Perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK  , then go to next step.
  2. Turn ignition on with engine off. If Malfunction Indicator Light (MIL) illuminates, go to next step. If MIL does not illuminate, go to step 4).
  3. Check for poor connections at battery feed circuit or ignition positive voltage 1 circuit. Repair as necessary. After repairs, go to step 22). If circuits are okay, go to step 5).
  4. Attempt to start engine. If engine starts, go to step 6). If engine does not start, go to step 7).
  5. Check for poor PCM ground connection on engine block or PCM connector ground terminals. Repair as necessary. After repairs, go to step 22).
  6. Turn ignition off. Disconnect PCM connectors. Turn ignition on. Using a test light connected to ground, probe MIL control circuit. See WIRING DIAGRAMS - 2.4L article. If MIL illuminates, go to step 8). If MIL does not illuminate, go to step 9).
  7. Check ignition and battery feed fuses. If fuses are okay, go to step 10). If fuses are blown, go to step 11).
  8. Check for poor battery feed, ignition positive voltage 1 or MIL control circuit connections. Repair as necessary. After repairs, go to step 22). If circuits are okay, go to step 12).
  9. If test light illuminates, go to step 13). If test light does not illuminate, go to step 14).
  10. Turn ignition off. Disconnect PCM connectors. Turn ignition on. Using a test light connected to ground, probe ignition positive voltage 2 circuit. See WIRING DIAGRAMS - 2.4L article. If test light illuminates, go to step 15). If test light does not illuminate, go to step 16).
  11. Check for short to ground in fuse circuit that was open. Repair as necessary and replace fuse. After repairs, go to step 22).
  12. Replace PCM. Perform PCM relearn procedures. After repairs, go to step 22).
  13. Repair short to voltage in MIL control circuit. After repairs, go to step 22).
  14. Check for open or poor connection in MIL control circuit. See WIRING DIAGRAMS - 2.4L article. Repair as necessary. After repairs, go to step 22). If circuit is okay, go to step 17).
  15. Using a test light connected to ground, probe ignition battery voltage 1 circuit. See WIRING DIAGRAMS - 2.4L article. If test light illuminates, go to step 18). If test light does not illuminate, go to step 19).
  16. Repair open in battery feed circuit. After repairs, go to step 22).
  17. Check for open in ignition feed circuit or fuse to MIL. See WIRING DIAGRAMS - 2.4L article. Repair as necessary. After repairs, go to step 22). If circuit or fuse is okay, go to step 20).
  18. Check for poor connections at battery feed circuit or ignition positive voltage 1 circuit. Repair as necessary. After repairs, go to step 22). If circuits are okay, go to step 21).
  19. Repair open in ignition positive voltage 1 circuit. After repairs, go to step 22).
  20. Replace Instrument Panel Cluster (IPC). After IPC replacement, go to step 22).
  21. Check for poor PCM ground connection on engine block or PCM connector. Repair as necessary. After repairs, go to next step. If connection and connector are okay, go to step 12).
  22. Warm engine to operating temperature. Check for DTCs. If DTCs are present, diagnose affected DTCs. If DTCs are not present, system is okay.
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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.