Circuit/System Testing

Ignition OFF, disconnect the harness connector at the EVAP canister.
Ignition ON, verify a test lamp illuminates between the ignition 1 voltage circuit terminal 9 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 terminal 8 and the ignition 1 voltage circuit terminal 9.
Ignition ON, command the EVAP vent solenoid ON and OFF with a scan tool. The test lamp should illuminate ON and OFF with each command.
- If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the PCM.
- If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If circuit tests normal, replace the PCM.
Test the EVAP vent solenoid for correct operation. Refer to Evaporative Emission Control System Diagnosis .
If the vent solenoid and circuits test normal, test for the following conditions:
- DTCs P2401 or P2402 are also set-Refer to DTC P2401 or P2402 .
- A blockage or restriction in the EVAP filter or passages between the filter and the EVAP canister
- A faulty EVAP canister-Refer to Evaporative Emission Control System Diagnosis .
- If all conditions are normal, replace the EVAP vacuum leak pump assembly.