LEMON Manuals: Even more car manuals for everyone
Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 438 (Engine Control System - Self-Diagnostics - 5.3L) >> System Tests >> Malfunction Indicator Lamp Inoperative >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2003 GMC Envoy XL and 2003 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
  1. Did you perform the Diagnostic System Check-Engine Controls? If yes, go to next step. If no, see DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS  under SELF-DIAGNOSTIC SYSTEM.
  2. Verify whether the instrument cluster is operational. If the Instrument Panel (IP) is completely inoperative, see appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. Command the MIL ON and OFF with a scan tool. Does the MIL turn ON and OFF when commanded with a scan tool? If yes, problem is intermittent. See INTERMITTENT CONDITIONS  under SELF-DIAGNOSTIC SYSTEM. If no, go to next step.
  3. Inspect the fuse that supplies ignition voltage to the instrument cluster. Is the fuse open? If yes, go to step  11. If no, go to next step.
  4. Turn OFF the ignition. Remove the fuse that supplies voltage to the instrument cluster. Disconnect the Powertrain Control Module (PCM) harness connectors. See COMPONENT LOCATIONS . Turn ON the ignition with the engine OFF. Measure the voltage from the MIL control circuit in the PCM harness connector to a good ground. Is the voltage less than .3 volt? If yes, go to next step. If no, go to step  11.
  5. Turn OFF the ignition. Install the fuse that supplies voltage to the cluster. Turn ON the ignition with the engine OFF. Connect a 3-amp fused jumper wire between the MIL control circuit in the PCM harness connector and a good ground. Is the MIL illuminated? If yes, go to step  9. If no, go to next step.
  6. Turn OFF the ignition. Remove the Instrument Panel Cluster (IPC). See appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. Turn ON the ignition. Probe the MIL battery positive voltage circuit at the IPC harness connector with a test lamp connected to a good ground. Does the test lamp illuminate? If yes, go to next step. If no, go to step  12.
  7. Test the MIL control circuit for an open or high resistance between the PCM and the IPC and repair as necessary. Did you find and correct the condition? If yes, go to step  15. If no, go to next step.
  8. Inspect for poor connections at the harness connector of the IPC and repair as necessary. Did you find and correct the condition? If yes, go to step  15. If no, go to step  13.
  9. Inspect for poor connections at the harness connector of the PCM and repair as necessary. Did you find and correct the condition? If yes, go to step  15. If no, go to step  14.
  10. Repair the short to ground in the MIL battery positive voltage circuit. Replace the fuse. After repairs, go to step  15.
  11. Repair the short to voltage in the MIL control circuit. After repairs, go to step  15.
  12. Repair the open in the ignition voltage circuit. After repairs, go to step  15.
  13. Repair or replace the IPC. See appropriate ANALOG INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. After repairs, go to step  15.
  14. Replace the PCM. See POWERTRAIN CONTROL MODULE under COMPUTERIZED ENGINE CONTROLS in REMOVAL & INSTALLATION - BRAVADA, ENVOY, ENVOY XL, TRAILBLAZER & TRAILBLAZER EXT article. Reprogram PCM. See POWERTRAIN CONTROL MODULE  under PROGRAMMING. After repairs, go to next step.
  15. Turn OFF the ignition for 30 seconds. Does the vehicle operate correctly, without any MIL illumination and without any stored DTCs? If yes, system is okay. If no, see DIAGNOSTIC TROUBLE CODE DEFINITIONS .
scientia non olet · About LEMON Manuals