A friend of mine has a civic hybrid that he's been driving for about 5 years. He bought it brand new, and now it has about 120,000 miles on it. He says he still gets about 40mpg. But there is a big problem. He told me the other day that he wanted to sell it due to its battery problem and catalytic converter. His dealer quoted about 5000 for repairs. Since he has a check engine light on, he can't pass emissions. If the hybrid burns cleaner than most gasoline engines and still achieves about 40mpg, is it still significant and necessary to have the check engine light turned off to have it pass emissions test? So basically, all the money saved over the 5 years of ownership is going back to the car if he decides to keep the car. It just turns me away from purchasing a hybrid.