Possible Causes

EVAP control system has a very large leak such as fuel filler cap fell off or EVAP control system does not operate properly. Possible causes are:

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