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Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1557 (Engine Controls And Fuel - 2.4L (Lat) - Troubleshooting & Diagnosis) >> Fuel Injector Circuit Diagnosis >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector at a fuel injector.
  2. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal A and ground.
    • If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test or replace the fuel injector.
  3. Ignition OFF, connect a J 44603  between the control circuit terminal B and the ignition circuit terminal A of each fuel injector one at a time.
  4. Engine cranking, the test lamp should flash for each injector.
    • If the test lamp is always ON, test the appropriate control circuit for a short to ground. If the circuit tests normal, replace the engine control module (ECM).
    • If the test lamp is always OFF, test the appropriate control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.
  5. If all circuits test normal, test or replace the fuel injector. Refer to Fuel Injector Diagnosis (w/J39021 or w/Tech 2)  or Fuel Injector Diagnosis (w/CH47976) .
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