P0453 CODE

P0453 is for the fuel tank pressure sensor. This code means that the voltage on the sensor was greater than 4.5V during key on engine off or during any engine operating mode.
Normal voltage from this sensor with no vacuum or pressure on the system should be 2.37 to 2.97V.
PCM sends a reference voltage of 5V to the sensor and tells if there is pressure or vacuum in the fuel tank by the voltage that returns from the sensor.

Possible causes are:

†FTP circuit open
†VREF shorted to VPWR
†Damaged PCM
†FTP circuit shorted to VREF or VPWR
†SIG RTN circuit open
†Damaged FTP sensor

Usually it is a loose connector at the sensor or a bad sensor.
It mounts on top of the fuel tank, has a 3 wire connector. To replace it you have to push down on it and twist, if I remember right CC.