This is one of the many problems I've had with this car but I just bought this car in january of 2010 with high hopes because of all the praise I had heard about prizms from previous prizm owners. However, beginning in March I noticed the check engine light come on. My dad said it shouldn't be a biggie and I should just wait until June for my inspection to get it checked. Silly me believed him and got it looked at for inspection. Two codes were read to me saying I had to fix the catalytic converter and that I needed the evaporation system checked. I've gotten the catalytic converter fixed and I had the evaporation system checked to say that it was the purge valve. I buy the purge valve and replace it myself and guess what, the light come right back on right after I get the code cleared. Got it brought back in and now they're guessing it's the charcoal canister. Number one, I have a few other problems on this car, number two it's 400 dollars for that piece and is a pain in the butt to replace, number three well my car isnt worth all this but I'm still paying off my loan and they're not even sure if that'll fix that problem.