I am getting a PO452 reading on my 2000 silverado. I have had it for 2 years and it runs fine. I now am trying to fix it and its driving me nuts. I have replace the fuel pump, gas cap, and the black thing that sits on top of the charcol box. I have checked and replace relays as well as the relays at my smog pump. And the smog pump works. What is it, why does this code keep coming back. I also have the scanner and erase the code but it just comes back in minutes.

The problem may be with the Fuel Tank Pressure (FTP) Sensor, which involves removing the fuel tank, or with the PCM. The PCM, for whatever reason, has a problem with the signal voltage coming from the FTP Sensor. It could be a FTP Sensor connection issue, but I doubt it. If you have access to a known good PCM, try substituting it before dropping the tank to replace the sensor.

I get code 0452 on my 2000 silveraldo 5.3. Replaced fuel pump,ftp sensor and wire connector. Went to several garages and dealerships with no luck. Pcm swap gave same code. Need to fix for inspection. Any ideas? Spent over a grand and am at same place when I started. Tried 2 fuel pumps and also gas cap. Truck runs fine but check engine light stays on.