Possible Causes

Malfunction is detected when EVAP system has a very large leak, such as fuel cap fell off, or if EVAP control system does not operate properly. Possible causes are:

• Fuel cap remains open or fails to close.
• Incorrect fuel tank vacuum relief valve.
• Incorrect fuel cap.
• Foreign matter in fuel cap.
• Leak in line between intake manifold and EVAP canister purge volume control solenoid valve.
• Foreign matter in EVAP canister vent control valve.
• EVAP canister or fuel tank leaks.
• Leak in EVAP purge line pipe and rubber hose.
• EVAP purge line rubber hose bent.
• Blocked or bent rubber hose to EVAP control system pressure sensor.
• Loose or disconnected rubber hose.
• EVAP canister vent control valve and circuit.
• EVAP canister purge volume control solenoid valve and circuit.
• Fuel tank temperature sensor.
• EVAP canister vent control valve "O" ring is missing or damaged.
• Defective EVAP control system pressure sensor.
• Fuel level sensor and circuit.
• Defective EVAP vapor cut valve.
• Leak in On-Board Refueling Vapor Recovery (ORVR) system.