Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the generator.
- Ignition ON engine OFF, observe the scan tool GEN-F Terminal Signal parameter, while repeatedly probing the generator field duty cycle circuit with a test lamp connected to battery positive voltage. The parameter should change from 0 percent to 99 percent.
- If the parameter was not affected by the test lamp, test the GEN-F Terminal Signal circuit terminal 2 for a short to ground or an open/high resistance. If the circuit tests normal, then replace the ECM.
- If the circuit tests normal, then replace the generator.