10 people reported this problem
Check Engine Light Due to Gas Cap or Catalytic Converter on Cadillac DeVille
5 people shared problem details
Check engine light comes on, check gas cap warning. Mine is caused by a rotted gas overflow line. Seems that it has rotted so bad that when I top off the gas tank, it started overflowing to the ground. It is also causing a miss in my engine when accelerating (not getting full power due to fuel pressure). Have not repaired yet but have found the fuel filler neck on eBay for $70.00. I was told you can cut off the bad section of the overflow, and clamp on a 3/4 ID fuel line. I am certain this would work, however if the line is that rotted I think I will install a new one for the $70 price.
1999 Cadillac DeVille80,000Visitor
Intermittant engine light due to gas filler cap. Replaced cap, but intermittant problems persists. No fix yet.
1998 Cadillac DeVille160,000Visitor
I keep getting MIl Code P0440, and have repaired everything in evap system w/o curing this problem.
1999 Cadillac DeVille116,000Visitor
check engine light on ... going to put new catalytic converter on Friday will let u know if it fixes th problem
1999 Cadillac DeVille55,000Visitor
check engine light comes on when gas reading reaches 8, 10 and 11 gals. Had new catalytic converter put on also o2 sensor thought everything would be alright, but when gas reading came down to 11 gals. check engine light came on again, had it check by computer and got the same reading as befor bad 02 sensor.
Illumination of the Check Engine Light may be the result of a loose or worn gas cap.
the car quit had to replace the whole fuel pump. since then the service engine light is on. i h...