Just want to add that you can buy an OBDII code reader for as little as $60.00 (I got one for $89.00). It plugs in under your dash in the diagnostic port very similar to plugging in an old dot matrix printer with the serial port connectors. You press read codes and they come on the screen. You can erase the codes with the reader, then see if the CEL comes on again. Of course, this also precludes having to disconnect battery cables (even if you don't buy the reader, buy a quick connect terminal end for the negative cable, it saves you from needing any tools on the road to disconnect/reconnect). Many times it's a one-off situation that doesn't perpetuate. Any many times, you get a clue so you're forearmed with at least some knowledge to prevent getting taken by disreputable or non-knowledgeable mechanics.
Just a suggestion. Knowledge is power.
