Conditions for Setting the DTC

P0451

• This DTC will set if the controller is unable to re-zero the fuel tank pressure sensor voltage within a calibrated range during the engine-off small leak test, P0442.
• The ECM must complete several engine off natural vacuum test tests before the diagnostic can turn the MIL ON or OFF.

P0452 

The fuel tank pressure sensor voltage is less than 0.15 V for greater than 10 s.

P0453 

The fuel tank pressure sensor voltage is greater than 4.85 V for greater than 10 s.

P0454

• If, during the engine-off natural vacuum small leak test, P0442, the ECM detects an abrupt fuel tank pressure signal change, other than a refueling event, this DTC will set. An abrupt change is defined as a change of greater than 0.45 in H2O in the span of 1 s but less than 1 in H2O in 12.5 ms.
• This test must fail twice in three samples to set this DTC.