| 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 (-3.5 kPa), or equal to or greater than .4 in. Hg (1.5 kPa) for 7 seconds or more. DTC P0451 is set if vapor pressure sensor output changes while 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