Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the generator.
- Ignition ON, engine OFF, connect a test lamp to B+ and repeatedly probe the generator field duty cycle circuit X1 terminal C, harness side while monitoring the scan tool ECM GEN-F Terminal Signal Parameter. It should change from 0 percent to above 95 percent.
- 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. If the circuit tests normal, replace the ECM.
- If the circuit tests normal replace the generator.