Q: Anyone know about check engine lights in Audis lighting up for no reason? I have a 2001 A6 Quattro. As far as I can tell there doesn't actually seem to be anything wrong. I don't want to take it in to the dealer if I don't have to.
A: the check engine light will come on whenever the PCM calculates that emissions will be over 50% higher than the threshold programmed into it. the most common reason would be the gas cap being improperly secured. if you gassed up in the 24 hours before the light came on, that could be why. many auto parts stores will check the codes for free. that will give you much more information about what direction to search for answers in. without knowing the particular code or codes that came up, the list of problems could be quite long and scary.