Pontiac Repair: Check gas cap, grand prix gtp, vent valve

Question
I have a 2005 Grand Prix GTP and the "check gas cap' me will not go off even after putting a new gas cap from Pontaic on the gas cap. Can you help me?

Answer
Hi Laurie:

More than likley a part in the emission system has failed on this car and it's not the gas cap as you figured out. I would highly advise you first off to make sure the new gas cap is the correct one for the car and not an aftermarket one. If so and it's the correct one ther is a part called an evap vent valve that goes bad on these cars and it will turn on the gas cap light. The vent calve is located behind the left rear wheel up in the wheel well near where you put the gas into the filler neck. They go bad on these car all the time. That would be my guess at to wht your gas cap light is on. Good luck :)