LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> GMC >> 1998 >> Forward Control 6.5 F >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Tests W/Codes - Introduction >> Self-Diagnostic System >> Mil On Steady >> 2.2L & 2.4L
April 5, 2026: LEMON Manuals is launched! Read the announcement.

2.2L & 2.4L

  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. Turn ignition on, with engine off. If MIL illuminates, go to next step. If MIL does not illuminate, go to MIL INOPERATIVE .
  3. Connect scan tool. Using scan tool, command MIL on and off. If MIL turns on and off as commanded, go to step  8. If MIL does not turn on and off as commanded, go to next step.
  4. Turn ignition off. Disconnect PCM connectors. Turn ignition on. If MIL does not illuminate, go to step  7. If MIL illuminates, go to next step.
  5. Check for short to ground in MIL control circuit. See appropriate wiring diagram in WIRING DIAGRAMS article. Repair as necessary. After repairs, go to step  8. If circuit is okay, go to next step.
  6. Replace instrument cluster. After repairs, go to step  8.
  7. Replace PCM. Perform PCM relearn procedures. After repairs, go to next step.
  8. Attempt to start engine. If engine starts and continues to run, go to next step. If engine does not start, or starts and stalls, go to step  1.
  9. Allow engine to reach normal operating temperature. Using scan tool, check for DTCs. If DTCs are present, diagnose DTCs. See DIAGNOSTIC TESTS in appropriate TESTS W/CODES article. If DTCs are not present, system is okay.
scientia non olet · About LEMON Manuals