System Check - Evaporative Emission System (EVAP)

Diagnostic Chart:

Wiring Diagram:

DIAGNOSIS
^ The EVAP system can be diagnosed by using [1][2]EVAP Control System Diagnosis.
^ EVAP canister purge valve operation is covered in this section and diagnosed in DTCs P0440, P0446, and P1441.
^ [1][2]EVAP vent solenoid operation is covered in this section and diagnosed in DTCs P0440, P0442, and P0446.
^ Fuel tank pressure sensor operation is covered in this section and diagnosed in DTCs P0440, P0442, P0446, P0452, P0453, P1441 and Evaporative Emission System Check.
^ A open or shorted circuit in the EVAP canister purge valve and [1][2]EVAP vent solenoid can also be diagnosed in PCM Outputs Diagnosis.

DIAGNOSTIC AIDS
Check for the following conditions:

^ Poor connection at PCM. Inspect harness connectors for the following conditions:

- Backed out terminals
- Improper mating
- Broken locks
- Improperly formed
- Damaged terminals
- Poor terminal to wire connection

^ Damaged harness. Inspect the wiring harness for damage. If the harness appears to be OK, observe the Fuel Tank Vacuum Pressure display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the display will indicate the location of the fault.
^ Incorrect purge or vacuum source line routing. Verify that the source vacuum and purge lines to the EVAP canister purge valve are not switched.