Problem Description and Possible Solution
A Loose or worn gas cap may cause Check Engine Light to illuminate.
Average mileage: 112,900 (60,000–167,000)
12 people reported this problem
On the instrument display I get a " check gas cap". I install a new cap and still have the same display. I did notice a raw gas smell coming from the left rear of car when this happens. I took car to a GM dealer and they tested the vapor problem. They tested the vapor system with a smoke test and a pressure test of the system. Could not find a problem. The system has many parts that can go bad: Fuel limiter vent valve, variable orifice valve, vapor canister vent solenoid, purge valve, fuel tank pressure sensor,. I will have to figure this one out. Maybe one of the parts will completely fail before I find the actual bad part.
The onboard diagnostic system gave me a check radiator cap notice. I check the cap and it was screwed on firmly. Apparently the cap is getting worn and it intermittently compromises the "Closed system". I have not had to replace the cap yet and the light has not come on in quite awhile. Until it comes on and stays on, I'll keep the old cap.