Diagnostic Aids
If a reasonable vacuum cannot be sustained for a specific time, a small leak will be indicated and DTC will set. A leak can be caused by any of the following conditions:
- Damaged or disconnected source vacuum hose.
- Damaged or leaking EVAP purge or vent hoses.
- Damaged or leaking fuel tank vapor hose.
- Faulty fuel tank pressure control valve.
- Faulty or loose fuel cap.
- Fuel level sensor malfunction.
- Fuel tank pressure sensor malfunction.
- Cracked or punctured EVAP canister.
- Leaking or faulty EVAP canister purge solenoid valve.
- Leaking or faulty EVAP fuel tank pressure control solenoid vacuum valve.
- Leaking or faulty EVAP canister vent solenoid.
- Leaking fuel sender assembly "O" ring.
- Leaking fuel tank or fuel filler neck.
Perform an inspection of all EVAP system components and vacuum hoses. See underhood vehicle emission control information label for component identification and vacuum hose routing.
An intermittent malfunction may be caused by a poor connection, rubbed-through wire insulation, or a wire broken inside insulation. Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, or poor terminal-to-wire connections before component replacement.