Sigh...new TSX owner with <500 miles and the malfunction light came on today. I know the most common problem is the gas cap not being tight, but I had gassed up last week. I did retighten just in case and drove 25 miles back home and it's still on.

A little disappointed right now with having to go back to a dealership so soon, but I'm hoping for a really stupid and simple problem to be fixed.

 

i had the same problem, at around 1.5k... they told me it was a bad fuel tank sensor of some sort.

 

Mine turned out to be a rear O2 sensor reading of some sort. They didn't change it, but just reset everything. So...maybe 15 minutes at the dealership