P0453

CIRCUIT DESCRIPTION
The fuel tank pressure (FTP) sensor measures the difference between the air pressure or vacuum in the evaporative emission (EVAP) system, and the outside air pressure. The control module supplies a 5-volt reference and a low reference circuit to the FTP sensor. The FTP sensor signal circuit voltage varies depending on EVAP system pressure or vacuum. If the FTP sensor signal voltage goes above a calibrated value, this DTC sets.




The table illustrates the relationship between FTP sensor signal voltage and the EVAP system pressure/vacuum.

CONDITIONS FOR RUNNING THE DTC
The engine is running.

CONDITIONS FOR SETTING THE DTC
^ The fuel tank pressure sensor voltage is more than 4.9 volts.
^ All conditions present for greater 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.
^ The DTC can be cleared by using a scan tool.

TEST DESCRIPTION

Steps 1-4:

Steps 5-14:

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