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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 422 (Engine Controls - System & Component Testing - 3.8L) >> Fuel Systems >> Fuel Injector Circuit Diagnosis (Impala & Monte CARLO) >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2003 Pontiac Grand Prix, 2003 Pontiac Bonneville, 2003 Chevrolet Monte Carlo, 2003 Chevrolet Impala, and 2003 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform Diagnostic System Check - Engine Controls. See DIAGNOSTIC SYSTEM CHECK - ENGINE CONTROLS under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. After performing Diagnostic System Check - Engine Controls, go to next step.
  2. Are any fuel injector DTCs set? If yes, go to DTC P0201-P0206: INJECTOR CONTROL CIRCUIT under DIAGNOSTIC TESTS in SELF-DIAGNOSTICS - 3.8L BONNEVILLE, GRAND PRIX, IMPALA, LESABRE, MONTE CARLO, PARK AVENUE & REGAL article. If no, go to next step.
  3. Check the fuel injector fuse. Is the fuel injector fuse open? If yes, go to next step. If no, go to step  6.
  4. Turn ignition switch to OFF position. Disconnect the fuel injector multi-way harness connector. Probe the fuel injector ignition 1 voltage supply circuit, fuse side, using a test light connected to battery voltage. Does the test light illuminate? If yes, go to step  9. If no, go to next step.
  5. Turn ignition switch to RUN position, engine OFF. Does the test light illuminate? If yes, go to step  13. If no, go to step  8.
  6. Turn ignition switch to OFF position. Disconnect the fuel injector multi-way harness connector. Turn ignition switch to RUN position, engine OFF. Probe the fuel injector ignition 1 voltage supply circuit using a test light connected to a good ground. Does the test light illuminate? If yes, go to next step. If no, go to step  10.
  7. Turn ignition switch to OFF position. Check for continuity between the ignition 1 voltage supply terminal and a fuel injector terminal, at the multi-way harness connector, fuel injector side. Does the DVOM display infinity? If yes, go to next step. If no, go to step  10.
  8. Check the fuel injector ignition 1 voltage supply circuit, between the multi-way harness connector and the fuel injectors for a short to ground. Did you find and correct the condition? If yes, go to step  14. If no, go to DIAGNOSTIC AIDS .
  9. Repair the short to ground in the fuel injector ignition 1 voltage supply circuit. After repair, go to step  14.
  10. Repair the open in the ignition 1 voltage supply circuit between the Underhood Bussed Electrical Center (UBEC) and the splice S109, located in the engine wiring harness, top of engine, at the IAT sensor breakout. After repair, go to step  14.
  11. Repair the fuel injector ignition 1 voltage supply circuit for an open and/or high resistance, between the multi-way connector and the splice. After repair, go to step  14.
  12. Repair the poor connection at the multi-way connector. After repair, go to step  14.
  13. Repair the short to a PCM ground in the fuel injector ignition 1 voltage supply circuit. After repair, go to next step.
  14. Operate the system to verify the repair. Did you correct the condition? If yes, system is okay at this time. If no, go to step  3.
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