DTC P0440: EVAP System Leak Detected (Gross Leak): Condition

DTC P0440 is set when EVAP system pressure varies more than predetermined pressure (EVAP system leak is detected) after EVAP canister purge valve was closed, pressure previously measured was less than predetermined value, and internal tank pressure was measured again. This circuit is monitored once per drive cycle. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. DTC P0455 is set when fuel tank pressure does not drop below a predetermined pressure (EVAP system leaking or plugged EVAP canister purge valve hose) when fuel tank is at a specified level, engine at normal operating temperature and not under high load, EVAP canister is purging, EVAP canister air valve closed, and EVAP canister purge valve open for a predetermined time. This circuit is monitored once per drive cycle. Possible causes are:

• Missing, loose or malfunctioning fuel filler cap.
• Loose or plugged vacuum hose.
• Components mounted to fuel tank leaking in aria of mounting.
• EVAP canister plugged.
• Open or short in EVAP system circuits.
• Canister purge valve malfunction.
• Canister air valve malfunction.
• Fuel tank pressure sensor malfunction.
• Fuel level sensor malfunction.
• Fuel tank component malfunction.