From what I've found, P0452 suggests there is a "short to ground" problem with the fuel pressure sensor. It's beyond my skill level to know if this means the sensor itself is defective or there could be another reason for the fault code such as a low voltage condition.
The part is pricey. I'd wait for a few other folks to comment before ordering it. As I understand it the sensor is located on top of the gas tank. See picture.
This picture came from the last poster in the following thread:
http://www.renntech.org/forums/topic/14454-tank-pressure-sensor-install-p0452-issue/