Diagnostic Aids

WARNING: This page is about a different car, the 2002 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

If DTC P0452 or P0453 is also set, diagnose that DTC first. See DTC P0452: EVAP FUEL TANK PRESSURE SENSOR CIRCUIT - LOW VOLTAGE or DTC P0453: EVAP FUEL TANK PRESSURE SENSOR CIRCUIT - HIGH VOLTAGE .

Fuel tank pressure sensor on scan tool should read 1.4-1.6 volts with ignition on, engine off and fuel cap removed. This represents atmospheric pressure or 0 in. Hg.

DTC P0451 indicates that the fuel tank pressure sensor signal voltage is skewed high or low. Possible causes of DTC P0451:

Corrosion in the fuel tank in-line harness connector.
Corrosion in the fuel tank pressure sensor harness connector.
Fuel tank pressure sensor skewed.

Inaccurate readings will occur if resistance measurements are taken on a fuel tank pressure sensor. The fuel tank pressure sensor contains an internal amplifier circuit that requires applied voltage to function properly.