One problem related to emission control has been reported for the 2001 Hyundai Sonata. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2001 Hyundai Sonata based on all problems reported for the 2001 Sonata.
Lower oxygen sensor malfunctioned, causing the "check engine" light to stay on. I have been returning to the suntrup dealership in missouri every since I purchased the car for the same exact problem. And the problem is always the oxygen sensors. I have a 2001 Hyundai Sonata and I have been having the same problems over and over. I had an extended warranty that I purchased with the car for $1,300. 00 and I find out on my last visit to the dealership that the warranty company filed bankruptcy. So now I have no warranty on my car and I have lost money for no reason.