So about a week ago I took the cl in for a CEL... when I picked it up the next day I asked what was wrong with it. They told me the used the code reader and no codes popped up, they reset the ecu and the CEL dissappeared. Well today driving home from school, it came on again exactly one week from the last time. Any ideas of what it is? TIA

 

If its throwing a CEL, it HAS to be a code. The cel isnt gonna come on for no reason.

Infact sometimes the ECU throws codes without the CEL even coming on, if they are minor ones.

Goto advance auto parts or a similar store where they will scan it and print out the results for you.