P0451

DTC P0451 Fuel Tank Pressure Sensor Signal Stuck

Wiring Diagram:

Circuit Description

The control module monitors the fuel tank pressure (FTP) sensor signal in order to detect vacuum decay and excess vacuum during the evaporative emission (EVAP) diagnostic test. The control module supplies a 5-volt reference and a low reference circuit to the FTP sensor. If the FTP sensor signal voltage is not within a calibrated value range during a cold engine start, this DTC sets.

Conditions for Setting the DTC

- The Fuel Tank Pressure signal variation is less than 58.7 mV.
- The Canister Purge flow variation is more than 1.0 kg/h.
- The Vehicle speed is more than 45 km/h.

Action Taken When the DTC Sets

- The Malfunction Indicator Lamp (MIL) will illuminate.
- The ECM will record operating conditions at the time the diagnostic fail. This information will be stored in the Freeze Frame and Failure Records buffers.
- A history DTC is stored.

Conditions for Clearing the MIL/DTC

- The MIL will turn off at the end of 3 consecutive ignition cycles in which the diagnostic runs without a fault.
- A history DTC will clear after 40 consecutive warm-up cycles without a fault.
- DTC(s) can be cleared by using the scan tool.

Diagnostic Aids

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.
The FTP sensor on the scan tool should be between 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.

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DTC P0451 - Fuel Tank Pressure Sensor Signal Stuck