check gas cap? check engine light on

[2000BRNZBON]

ok guys Im new here and have a question on my 2000bonny w/sc
the check engine light keeps coming on and the computer is telling me to check gas cap i have replaced the gas cap and reset the computer with the scanner it was ok for a day and now it came back on i have checked both the original and new cap for defects and there are none I can see anyone have an idea whats going on here?

[bonnevillain]

was the code specifically for the gas cap, or was it an EVAP emissions code, and someone told you it could be the gas cap?

i would try cleaning the metal part that the cap goes onto, make sure it is not rusty or anything.

[Archon]

Did you check the sealing surface on the filler tube for the gas cap? That often gets quite rusty, and can cause the cap not to seal properly.

[93 SSE 4 ME]

I hope you have better luck with this than I've had. Mine's throwing a P0455 code that won't go away. I've cleaned the filler neck, replaced the gas cap, replaced the fuel tank pressure sending unit, cleaned the evap vent valve and the evap solenoid. And it still throws the code. I've become accustomed to resetting the "check gas cap" message as soon as I get in the car, and SES light has become part of the enviroment. The local Pontiac dealer wants to do a bunch of extensive testing (as reccommended by a TSB), and then it's required thru the TSB that a regional service rep be contacted if the issue still isn't solved. So i'm living with it...

Mark

[sco99888]

bring it to a mechanic and have them blow smoke in it that will tell you where your leak is,the leak can be as small as a pin hole i had the same problems come to find out it was a tiny crack on the pipe going to the tank,threw some liquid metal on it has not come back on since.

[93 SSE 4 ME]

A smoke test is next in line. Good to hear that someone actually got this thing resolved.

Mark

[00ssei]

same here, i think its my gas cap though, but i havent replaced my gas cap yet. WHY? well because i want the original gas cap that hangs on the gas door and those cost $25, im trying to find one on ebay. But, if you already changed the gas cap and cleaned everything, it should be a leak somewhere.

Good luck.

[crash93ssei]

Smoke test..... I have never heard of that before. Sounds like a good idea though. It would be much easier to track down a cracked / split line that way

[kcoop99]

How do they do this smoke test??? Sounds interesting. Mine is throwing that code and not sure why. Thanks!

[sco99888]

i belive it is the same way they smoke the engine to find leak's in the gaskets.

[00Beast]

they seal off the gas filler, and pump an artificial smoke in, like the kind used at rock concerts, and if you can see smoke, there is a leak somewhere.