Code Definition
- DTC P0440: EVAP System Malfunction
- DTC P0442: EVAP System Leak Detected (Small Leak)
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM connectors and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. If ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. For programming procedures, see COMPUTER RELEARN PROCEDURES - IMPORT article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT. |
Note. If DTC P0441, DTC P0446, DTC P0450 or DTC P0451 is output after DTC P0440 or DTC P0442, perform appropriate test first before performing DTC P0440 or DTC P0442 test.
Note. For component location, see appropriate illustration in THEORY & OPERATION article.
Circuit Description
Vapor pressure sensor, canister closed valve VSV and pressure switching valve VSV are used to detect faults in EVAP system. DTC is set if EVAP system leak is detected or vapor pressure sensor malfunctions. Possible causes are
- Damaged, disconnected or blocked vacuum hose(s).
- Fuel tank cap is installed incorrectly.
- Defective fuel tank cap.
- Damaged, cracked or disconnected vacuum hoses.
- Damaged fuel tank.
- Defective charcoal canister.
- Vapor pressure sensor circuit is open or shorted.
- Defective vapor pressure sensor.
- Defective fuel tank overfill valve.
- Defective ECM.
Diagnostic Aids
Ask customer if fuel tank cap has been left off or not completely tightened recently. This may cause DTC to be set. Using scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.