Circuit/System Testing
- Ignition OFF, disconnect the harness connector of the EVAP vent solenoid.
- Ignition ON, verify a test lamp illuminates between the ignition 1 voltage circuit and ground.
- If the test lamp does not illuminate, test the ignition 1 voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition 1 voltage circuit fuse is open, test all components connected to the ignition 1 voltage circuit and replace as necessary.
- Ignition OFF, connect a test lamp between the control circuit and the ignition 1 voltage.
- Ignition ON, with a scan tool, command the EVAP vent solenoid ON and OFF. The test lamp should respond to the commanded state.
- If the test lamp remains ON all the time, test for a short to ground on the control circuit. If circuit/connections test normal, replace the ECM.
- If the test lamp remains OFF all the time, test for a short to voltage or an open/high resistance on the control circuit. If circuit/connections test normal, replace the ECM.
- If all circuits/connections test normal, test or replace the EVAP vent solenoid.