Why would a check engine light come on? My car does not seem to be having any problems? Is this standard?
I recently had a friend of mine do an oil change on my Volvo S40 2003 (He said he knew how to do it)...now a week later my check engine light has come on and won't go off.... the car seems to run ok?
There are a lot of reasons the light can come on and not affect the way the car runs. Your friend did nothing wrong in changing your oil. The light is probably on because of an emission or EVAP problem. Neither are a big deal unless you need to pass emissions test. However, get the code looked at just in case it could be something else. Autozone will check it for free.
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