Diagnostic Aids

NOTE: If DTC P0452 or P0453 are also set, diagnose that DTC first.

NOTE: Inaccurate readings will occur if resistance measurements are taken on a fuel tank pressure sensor. The Fuel Tank Pressure (FTP) sensor contains an internal amplifier circuit that requires applied voltage to function properly.

The FTP sensor on the scan tool should be 2.35-2.85 volts with the ignition ON and the engine OFF and the fuel cap removed. This represents atmospheric pressure, or 0 inches of vacuum.

DTC P0451 indicates that the fuel tank pressure sensor signal voltage is skewed. Possible causes of DTC P0451 are as follows:

Corrosion in the fuel tank inline harness connector.
Corrosion in the engine I/P inline harness connector.
Corrosion in the FTP sensor harness connector.
The FTP sensor skewed.

For intermittent conditions, see INTERMITTENT CONDITIONS under SELF-DIAGNOSTIC SYSTEM.