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 more 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 to set this DTC.