LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Pontiac >> 2001 >> Aztek Base, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Basic Diagnostic Procedures >> Basic Fuel System Checks (Gasoline) >> Injector Circuit Diagnosis >> 4.3L, 5.0L & 5.7L
April 5, 2026: LEMON Manuals is launched! Read the announcement.

4.3L, 5.0L & 5.7L

  1. Perform OBD system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK in appropriate SELF-DIAGNOSTICS article. After performing OBD system check, go to next step.
  2. Disconnect injector harness connector at intake manifold. Turn ignition on. Using test light connected to ground, probe injector ignition feed circuits. If test light illuminates at all injector feed circuits, go to step  6. If test light does not illuminate at all injector feed circuits, go to next step.
  3. If test light illuminates for only some of the injector circuits, go to step  5. If test light does not illuminate for any injector circuit, go to next step.
  4. Check ECM I fuse (20-amp), located in underhood fuse block. If fuse is open, go to step  10. If fuse is okay, go to step  11.
  5. Check for open in faulty injector feed circuit. After locating faulty circuit, go to step  12.
  6. Install injector test light to each injector circuit, one at a time. Crank engine. If injector test light flashes for each injector, check fuel injector(s). See FUEL SYSTEM in appropriate SYSTEM & COMPONENT TESTING article. If injector test light does not flash for each injector circuit, go to next step.
  7. If injector test light was on steady for any injector circuit, go to next step. If injector test light did not illuminate for any injector circuit, go to step  9.
  8. Install injector test light on faulty injector circuit. Turn ignition off. Disconnect VCM harness connector (Red). Turn ignition on. If injector test light is off, go to step  16. If injector test light remains illuminated, go to step  13.
  9. Check for open or short to voltage in injector control circuit. If circuit is open or shorted, go to step  12. If circuit is okay, go to step  14.
  10. Check for short to ground in injector control circuit. After locating short, go to step  12.
  11. Repair open or short to ground on all injector feed circuits. After repairs, go to step  17.
  12. Repair circuit as necessary. After repairs, go to step  17.
  13. Repair short to ground in injector control circuit. After repairs, go to step  17.
  14. Check terminal contact at VCM harness connector. If terminal contact is faulty, go to next step. If terminal contact is okay, go to step  16.
  15. Repair terminal contact as necessary. After repairs, go to step  17.
  16. Replace VCM. Perform VCM reprogramming procedures. After repairs, go to next step.
  17. Using scan tool, select DTC, CLEAR INFO function. 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  2.
  18. Allow engine to reach normal operating temperature. Using scan tool, select DTC, FAILED THIS IGN function. If any other DTCs are set, diagnose DTCs. See appropriate SELF-DIAGNOSTICS article. If no other DTCs are set, go to next step.
  19. Using scan tool, select CAPTURE INFO, REVIEW INFO function. If additional undiagnosed DTCs are set, diagnose DTCs. See appropriate SELF-DIAGNOSTICS article. If additional DTCs are not present, system is okay.
scientia non olet · About LEMON Manuals