Why does the message "service emissions" keeping lighting up in my Cadillac DeVille?

Answer by  Allstar (2071)

Something in the emission control system--probably an oxygen sensor in the exhaust--isn't working right. It might run fine, but it might be polluting more than it should.

Answer by  fs (41)

The vehicle may be running fine to you but it may in fact be running poorly. All emission related items should be serviced as soon as possible. This is because serious damage could be caused to your emission system by disregarding the warning. The warning light may be caused by misfires, faulty sensors, or some other mechanical,electrical or electronic falure.

Answer by  kennethjgoodson (4903)

That means that you probably have a bad O-2 sensor or there is a leak in your vaccum system. You will probably start to notice your burning gas bad.

Answer by  turborotary91 (256)

one or two things.either u have a bad oxygen sensor which doesnt always make ur car run badly or an exhaust leak either way it will not pass emissions testing

Answer by  Amber40 (24961)

It sounds like that light is used to indicate that there is a problem in your emission system. The car may be running fine now but the light might be trying to tell you to correct something before something major has a problem. Check the codes to find the problem.