| DTC | Affected Circuit |
|---|---|
| P0450 | EVAP Pressure Sensor Malfunction |
| P0451 | EVAP Pressure Sensor Range/Performance Problem |
DTC IDENTIFICATION
| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. |
Circuit Description
Vapor pressure sensor and Vacuum Switching Valve (VSV) for vapor pressure sensor are used to detect faults in EVAP system.
DTC P0450 is set if 10 seconds after engine starts, vapor pressure sensor reading is less than -1.0 in. Hg, or .4 in. Hg or more for 7 seconds or more. DTC P0451 is set if vapor pressure sensor output changes wile vehicle is standing at idle and vapor pressure sensor VSV is on. Possible causes are
- Short or open in vapor pressure sensor circuit.
- Vapor pressure sensor.
- ECM.
Note. If DTCs P0110, P0115, P0120, P0450 and P1120 are output together, inspect ECM terminal E2 (ground) circuit for an open. Repair as necessary. See appropriate wiring diagram in SYSTEM WIRING DIAGRAMS article.
Note. If DTC P0441, P0446, P0450 or P0451 is output after DTC P0440, perform appropriate circuit test first before performing DTC P0440 test.