I posted recently that I'd just bought an 01 Prius. A check engine light had been on and I'd had the owner get that taken care of at the dealer before I bought it. After I bought it, it came back on the next day. After some research here I read up on the likely problem given the error codes. Sure enough, dealer said part of the exhaust assembly would need to be replaced. Fortunately, it's covered under the emissions warranty. Whew! Part is ordered, should be replaced next week. It hasn't affected driving, more just my sense of aesthetics, having the light blemishing my otherwise fine car Now I just need to figure out what to do about the nonfunctioning CD player...