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 if a fault is present in EVAP system based on vapor pressure signal circuit.
DTC P0441 or P0446 is set if EVAP system leak is detected by ECM or if there is a malfunction in EVAP VSV, pressure switching valve VSV, or in vapor pressure sensor. Possible causes are:
- Disconnected, cracked, damaged or blocked vacuum hose.
- Fuel tank cap installed incorrectly.
- Damaged fuel tank cap.
- Open or short circuit in vapor pressure sensor circuit.
- Faulty vapor pressure sensor.
- Open or short in EVAP VSV circuit.
- Faulty EVAP VSV.
- Open or short in canister closed valve VSV circuit.
- Faulty canister closed valve VSV.
- Open or short in pressure switching valve VSV circuit.
- Faulty pressure switching valve VSV.
- Damaged fuel tank.
- Faulty charcoal canister.
- Damaged fuel tank overfill check valve.
- Faulty ECM.
NOTE:
If DTC P0441, P0446, P0450 or P0451 is output after DTC P0440, perform appropriate diagnostic test first before performing DTC P0440 diagnostic test.