| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM connectors and ground circuits are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
Note. If DTCs P0110, P0115, P0120, P0440, P0441, P0446, P0450 and P0451 are output together, inspect ECM E2 circuit (sensor ground) between ECM and splice I8. Repair as necessary. See WIRING DIAGRAMS article.
Note. If DTC P0441, P0446, P0450 or P0451 is output after DTC P0440 or P0442, perform appropriate test first before performing DTC P0440 test.
Note. For component location, see appropriate illustration in THEORY & OPERATION article.
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 scan tool, read FREEZE FRAME data. Freeze frame data records engine conditions when malfunction is detected.