Where is the evaporator pressure switch on a 04 f150 4.6l

Question

My truck check engine light came on and is shooting out a code of p0452 where do I start checking

Answer 1

P0452 Evaporative emission system pressure sensor low input

This code is for the fuel tank pressure sensor, What the ECM does is look for open circuit  , short circuit , grounds rationality, low input circuit are when the reference voltage to that component is not within the specifications. You can install a fuel tank pressure sensor in its place without installing the sensor and retest, what you want to occur is a evap code, and not a circuit low input code, Circuit low input code are usually the ECM, that or test the fuel tank pressure sensor reference voltage, with key on engine off, you should have no less that 4.50 volts.