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Circuit/System Testing

WARNING: This page is about a different car, the 2007 Chevrolet Monte Carlo and 2007 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector at the generator.
  2. Ignition ON, and the engine OFF, connect a test lamp to battery positive voltage and repeatedly probe the generator field duty cycle circuit, harness side while monitoring the GEN-F Terminal Signal Parameter in the ECM data list. It should change from 0 percent to above 95 percent.
    • If the GEN-F Terminal Signal parameter was not affected by the test lamp, test the GEN-F Terminal Signal circuit for a short to voltage,short to ground, a high resistance, or an open circuit. If the circuit tests normal,replace the ECM.
  3. If the circuit tests normal during the Ignition On / Run tests,and ECM parameter changed from 0 percent to above 95 percent replace the generator.
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