P1440 - EVAP Emission Control System Leak Detected (Small Leak)

The Evaporative Emission (EVAP) pressure sensor, the manifold absolute pressure/barometric pressure (MAP/BARO) pressure sensor, and the fuel tank temperature sensor circuits are monitored by the Powertrain Control Module (PCM). With the fuel tank fuel vapor pressure applied to the EVAP system through the EVAP vacuum cut bypass valve, while the EVAP canister vent valve is closed and the EVAP canister purge valve is closed, the leak test fails when the EVAP pressure sensor signal to the Powertrain Control Module (PCM) does not rise accordingly to the calculated fuel vapor pressure obtained from the fuel tank temperature sensor signal sent to the PCM.

Possible Causes:
^ Incorrect fuel tank vacuum relief valve
^ Incorrect fuel filler cap used
^ Fuel filler cap remains open or fails to close
^ Foreign matter caught in the fuel tiller cap
^ Leak in the line between the intake manifold and the EVAP canister purge valve.
^ Foreign matter caught in EVAP canister vent control valve.
^ EVAP canister or fuel tank leaks
^ EVAP purge line leaks
^ EVAP purge line bent
^ Blocked or bent line to the EVAP pressure sensor
^ Loose or disconnected rubber tube
^ EVAP canister vent control valve or circuit
^ EVAP canister purge valve or circuit
^ MAP/BARO pressure sensor or circuit
^ MAP/BARO solenoid valve or circuit
^ Fuel tank temperature sensor
^ Blocked or bent hose to the MAP/BARO pressure sensor
^ O-ring of the EVAP canister vent control valve is damaged or missing
^ Water separator
^ EVAP canister is saturated with water
^ EVAP pressure sensor

Diagnostic Aids:
With the EVAP canister purge valve closed, the EVAP canister vent valve closed, the vacuum cut by-pass valve open, and apply 0.2 - 0.4 psi (1.37 - 2.76 kPa) pressure to the EVAP emissions test port, the EVAPRES PID should increase from the EVAPRES PID value with no pressure applied to the EVAP system.