P0453

CIRCUIT DESCRIPTION
The control module monitors the fuel tank pressure (FTP) sensor signal in order to detect vacuum decay and excess vacuum during the enhanced evaporative emission (EVAP) diagnostic. The control module supplies a 5-volt reference and ground to the sensor. The FTP sensor signal voltage increases as the FTP decreases, negative pressure or vacuum, high voltage. The FTP sensor signal voltage decreases as the FTP increases, positive pressure, low voltage. When the FTP sensor signal goes above a predetermined value, DTC P0453 will set.

CONDITIONS FOR RUNNING THE DTC
The engine is running.

CONDITIONS FOR SETTING THE DTC
^ The FTP sensor voltage is more than 4.9 volts.
^ All conditions are present for more than 5 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The control module will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test ran and failed.
^ The control module will store conditions which were present when the DTC set as Freeze Frame/Failure Records data.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The control module will turn OFF the MIL during the third consecutive trip in which the diagnostic ran and passed.
^ The history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ Use the scan tool in order to clear the DTC.

TEST DESCRIPTION

Steps 1-5:

Steps 6-14:

The number below refers to the step number on the diagnostic table.
2. If DTC P1635 or P1639 are set, the 5-volt reference circuit is shorted to a voltage.