DTC P0451: EVAP Fuel Tank Pressure Sensor Circuit Performance: Description

The function of the fuel pressure sensor is solely for EVAP leak diagnostics. Fuel tank pressure sensor is a transducer that varies resistance to changes in fuel tank pressure (difference between fuel tank and outside air pressure). ECM measures signal voltage from fuel tank pressure sensor, which is a reduced value of ECCM 5-volt reference. Signal voltage will read low when pressure in fuel tank is low (vacuum) and will increase as pressure in tank increases. DTC sets when signal voltage at ECM is more than calibrated voltage value for an extended period of time.