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Circuit/System Testing

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  1. Ignition OFF, disconnect the harness connector at the generator.
  2. Ignition ON, test for less than 1 volt between the generator turn on signal circuit terminal 1 and ground.
    • If greater than the specified range, test the generator turn on signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  3. Engine running, test for greater than 3.5 volts between the generator turn on signal circuit and ground.
    • If less than the specified range, test the generator turn on signal circuit for a short to ground, an open or a high resistance. If the circuit tests normal, replace the ECM.
  4. If the circuit tests normal, replace the generator.