error code 452 and light auto turn on on 2000 GMC Safari

I have an intermittent code 452. the service engine light will come on, check the code get 452. Without doing anything to vehicle the light will go out in couple days. No code. then couple days later will come on again an repeat. Any thoughts. Also how can I turn off the module/switch that turns on the headlights when it is dark/dusk?

by in Marana, AZ on June 12, 2011
1 answer 1 comment
ANSWER by on June 12, 2011
Error code P0452 has to do with a fault with your Fuel Tank Pressure Sensor. When a sensor is going out, often times it will set the code and then it will work fine and the code will clear and then it will 'act up' again and the code will re-set. Think of an old TV, when it starts to go out, if you smack it on top, it may work for awhile, but eventually it fails and you need a new TV. Same thing with these electronic sensors. The only way to completely resolve the issue is to repair the problem, which in most cases is a defective sensor., unless you had a new fuel pump installed. If that is the case, it may be due to an improper repair, i.e a leak in the rubber seal ring in the fuel tank, an improperly installed sensor or chafed or pinched wiring. As for the head lights, you need to have the Twilight Sentinel feature for your Van, if you have it then look at your head light switch and find the Twilight Sentinel setting. It should also be explained in your owner's manual.
COMMENT by on June 12, 2011
Did have the fuel pump replaced recently. Light started to come on intermittently a few weeks after that. It is hard to believe a leak in the seal would be intermittent same for improperly installed sensor. Seems like those would be continuous. Will check for pinched or chafed wiring. Also will see if can find anything in manual about lights. Thanks for you reply.