DTC P0442 Or DTC P0455: Condition

DTC P0455 is set if fuel tank internal pressure does not drop below a specified value within a specified time, and it raises varying above a specified value a gross leak in EVAP system is detected. Fuel tank must be at least 1/4 full, engine must be running at normal operating temperature and EVAP canister purging. ECM monitors this circuit once per drive cycle.

DTC P0442 is set when Fuel Tank Pressure (FTP) after a specified time varies more than specified value, a small leak in EVAP system is detected. Fuel tank must be at least 1/4 full, engine must be running at normal operating temperature and EVAP canister purging. ECM monitors this circuit once per drive cycle. Possible causes are:

• Missing, loose or malfunctioning fuel filler cap, or leak from cap gasket.
• Loose or plugged vacuum hose.
• Leaking fuel pump assembly seal on fuel tank.
• Open or short in EVAP system circuits.
• CPV malfunction.
• FTP sensor malfunction.
• Fuel level sensor malfunction.
• Fuel tank component malfunction.
• ECM malfunction.