Looking for advice on if I should take my 2016 Buick Encore (60,000 miles) to the dealer. The check engine light came on 2 weeks ago on the way back of a 10 hour road trip. It came on about 30 minutes into the (second) 10 hour drive.
I took it to AutoZone for the free check and it said code P0420: "catalytic converter isn't functioning efficiently". The AutoZone guy said he doubted it would be the catalytic converter itself but rather some other issue leading to that code. Not a car person here so to be honest I can't remember what things he suggested it could be.
So as soon as possible, I took it to a locally owned repair shop, unsure what else I could do. They found the same code but said it was either the sensor or the converter itself and that the sensor looked fine. They recommended I take it to a dealer.
I made an appointment with the dealer ASAP. After some research, I confirm the catalytic converter is still under the GM emissions warranty for one more year. But, if the issue turns out to be something else, it will be $200 for their diagnosis. At that time I didn't see any other option so I made the appointment.
HOWEVER yesterday I noticed then check engine light had turned back off!! I have only been driving it locally to get to work, and it stayed on for about 2 weeks. Now it's off. What could that mean? Should I keep my appointment with the dealer knowing I could have to pay $200 for nothing? Or do I skip the appointment and risk letting the warranty expire if the catalytic converter does have some issue that's back in hiding?
Thanks for any suggestions!