Cadillac DeVille Problems

Check Engine Light Due to Gas Cap Issue on Cadillac DeVille

Problem Description and Possible Solution

Illumination of the Check Engine Light may be the result of a loose or worn gas cap.

(62 people reported this problem)

Cadillac DeVille Vehicles With This Problem

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Average mileage: 99,424 (25,500–194,000)
9 model years affected: 1996, 1997, 1999, 2000, more2001, 2002, 2003, 2004, 2005
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Viewing 1-20 of 23 comments
Code came up with very small vacuum leak in evaporator system or also Check Gas Cap. I originally fixed the problem by dabbing a small amount of grease on the rim of the gas filler neck. But after a year or so I finally figured out the problem. The gas cap is a poor design. I tore apart the gas cap and found out the seal that is really a like a rubber grommet does not contact the rim of the filler neck properly. I took a piece of single strand copper wire and wrapped it around the back side of the seal (side closest to the handle of the cap) forcing the seal closer to the rim side of the filler neck. Problem solved.
check gas cap comes on on the dash replaced cap 3 times still comes on have reset computer everytime
i have had these code off and on for about an year and i keep like a fool replacing the cap and the problem never goes away until it just wants to. i do not know why it does it but it comes and goes and no one knows why.
I got the warning. I took the gas cap off, cleaned it and applied some light silicon lubricant and the problem hasn't come back in a couple of years now. I did NOT replace the cap... just cleaned it.
I replaced the gas cap and it is still and issues. I suspect there is a vacuum leak somewhere around the gas tank.
Gas cap causes sensor to trigger the service light. Small vac leak. and as everyone know the heads are leaky but i love her ;) lol called the dealer $35 for a new gas cap with the factory harness 99 for the win!
replaced cap multiple times from dealer. finally they must have felt sorry for me and told me to clean the cap really well...toothbrush & water...dry well with lint free cloth. It worked!!! have to do about every six months as error codes starts again. Still doing @ 102,000 miles...looks like they would have fixed this by now!!!!!
Service engine light on and evap code. Both (99,400 and 14,300)times resolved with new cap. Seems like cap should last longer.
My faulty cap was replace 3 times. Engine light goes off then back on. Seems like this should be a recalled item. Using the same faulty cap over and over does not solve the problem. My mechanic informed me that Cadillac Deville 2003 has pages and pages of recalled parts. When I asked Cadillac about this they said my recalls were closed. I interpreted that to mean they cannot afford to keep replacing recalled parts with more faulty parts. Done with Cadillac! Have spent thousands and thousands on maintenance including a transmission rebuild, and now most recently oil leak and coolant leak...sheesh!
Service Engine Soon Light came on. Reseated the cap many times. Changed fuel brands and used 3 additional tanks of fuel. Dealer said the seal in the cap goes bad and they do not sell a replacement seal. New cap solved the problem immediately.
had to buy new fuel cap. then had to wait two days for sensor to register the new fuel had been installed before light went off.
just noticed check gas cap display showing at the same time check ingine light came on. I made sure cap was on tight and that made no difference?