Contour Enthusiasts Group Archives Forums General Troubleshooting CEL On, then Goes away

98 Mystique LS, 6 Cyl. The light came on while driving high speed on the highway.
Don't yell, but I didn't bring the car right in. I drive it only around town most of the time.
Well, the other day I went on a short errand and the CEL light is not on anymore. I checked for
a burned out light bulb.

I realize I should bring it to the dealer soon, but what would make the light go on, then off after
a while?

Thanks,
Andy

my fathers cel in his 95 Se would cycle on the highway. He got the injectors cleaned and that helped some. The other weekend he looked at the plugs and found the front bank was just a bit dark so he replaced the O2 sense, didn't cure the cel but he said it ran better and might just be some time befoer the computer learns the new sensor. I asked once before and someone said it was a hose that got nicked and at highway speed it was enough to draw air in IIRC, or something like that. So maybe it is something like that

The CEL is a signal by the "On Board Computer" that a problem is sensed. There are many reasons. The light will go off if the computer no longer senses the problem. The computer will register the problem as a code which is put in memory. The computer will remember the last several codes. The CEL is related to emissions problems, many which can result in poor driveabilty and performance. The O2 sensors in the V6 are a common problem. After about 50K miles they are prone to vary. This tells the computer that there is a problem. There may not be an engine problem, but rather a "sensor" problem. Bad thing is that the computer may "believe" the sensor and adjust something else, resulting in poor performance and gas mileage.
Anyway... it's common for the light to come on and go off. As the problem worsens(they usually do), the light will be on more. Take the car to a dealer or other service center to get the codes read and diagnosed. Some auto stores will provide the code reading (and maybe advice). Good luck.

Al