Check Engine Light Due to Gas Cap Issue on Pontiac Bonneville

Problem Description and Possible Solution

Illumination of the Check Engine Light can be caused by a loose or worn gas cap.

Problem Data
RepairPal Verified
Average mileage: 132,230 (112,372–189,000)
10 model years affected: 1996, 1997, 1998, 1999, more2000, 2001, 2002, 2003, 2004, 2005
25 people reported this problem
Viewing 1 - 5 of 5 problem details
For as long as I can remember the check engine light is on. Replaced the gas cap. Works for about a week. Light back on. I gave up
The check engine/service engine light comes on with an issue with the EVAP system. Using a scan tool you code that comes up will either be a P0440 or P0442 code. This issue is very common with pontiac bonneville models and also the pontiac gran prix models. You can fix the issue by replacing the gas cap. This will cost anywhere from $10-$30 (this will fix this issue roughly 80% of the time) or you will have to replace eithe the EVAP canister, an EVAP solenoid, or a leak in one of the lines. This will cost about $20-$40.
And I have a brand new gas cap from auto zone for my make and model and it's still happening, cleared the computer n all.
When I put my gas cap on, I have to turn it past being on. I turn it until it clicks several times. Otherwise, my service engine light comes on.
my check engine light has came on and there is nothing wrong with it