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Circuit/System Testing

WARNING: This page is about a different car, the 2008 Cadillac STS. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the generator harness connector.
  2. Ignition ON and engine OFF, connect a test lamp to B+ and repeatedly probe the generator field duty cycle circuit terminal 2, harness side while monitoring the GEN-F Terminal Signal Parameter. It should change from 0 percent to above 95 percent.
    • If the circuit tests nor mal, replace the generator.
    • If the parameter was not affected by the test lamp, test the circuit for a short to voltage, short to ground, or an open/high resistance.
  3. If the circuit tests, replace the ECM.
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