Circuit Description

Vapor pressure sensor, canister closed valve Vacuum Switching Valve (VSV) and pressure switching valve VSV are used to detect faults in EVAP system. ECM determines is a fault is present in EVAP system based on the vapor pressure signal circuit. DTC P0440 is set if EVAP system leak is detected in EVAP system components between fuel tank and charcoal canister or vapor pressure sensor malfunctions. Possible causes are:

Faulty vapor pressure sensor.
Fuel tank cap installed incorrectly.
Fuel tank cap defective.
Damaged, disconnected or blocked vacuum hose.
Fuel tank damaged.
Charcoal canister damaged.
Hose between fuel tank and charcoal canister damaged.
Open or short in vapor pressure sensor circuit.
Fuel tank overfill check valve damaged.
Faulty ECM.

NOTE: If DTC P0441, P0446, P0450 or P0451 is output after DTC P0440, perform appropriate circuit test first before performing DTC P0440 test.