CarTalk.com Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

2009 Mitsubishi Eclipse catalytic converter

My check engine light came on. I took it to my mechanic. He ran a diagnostic check and advised it ‘is flagging for the catalytic converter’. He ordered the part. I dropped the vehicle off. He tore down the vehicle and realized he had ordered the wrong catalytic converter. He put the vehicle back together and told me I could drive it until he gets the correct part in. My check engine light has gone off. Does that mean I did not need a new catalytic converter? I have over 130k miles.

The downstream oxygen sensor is the part that checks if the converter is bad. The computer was probably reset when your mechanic worked on it. When the oxygen sensor picks up on the bad converter, your engine light will turn on again, if indeed you have a bad converter. It may take a while for the light to turn on though. The converter can be marginally bad and it’s performance can be checked with a professional scan tool. So your mechanic may well be right.

Thank you. When I picked it up the check engine light was still on. By the end of the day, it had turned off. It has been a couple of days and it is still off. But based on your comment, it is a matter of time. So, i will let him do the work.

You might want to have a discussion with your mechanic and see what he thinks about the light going out. But he will know more than anyone on the issue because he has eyes on it. Sometimes an exhaust leak can cause the OWNER sensor to give a false reading, and he might have inadvertently fixed it when he put it back together. Again he can see what I can’t so just ask him to take a second look.

Thank you!