| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM connectors and ground circuits are okay. If either are defective, 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.
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. DTC is set if vapor pressure sensor malfunctions. Possible causes are
- Vapor pressure sensor circuit is open or shorted.
- Defective vapor pressure sensor.
- Defective ECM.
Diagnostic Aids
Using Toyota hand-held tester or scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.