I have a 2011 hyundai sonata limited 2.0 and the engine light keeps coming on. I have taken to the dealer 4 times and they can't seem to fix this. Does anyone know why this is happening?

OK- I'm going to take a minute to help you- to find your way out of the heavy fog cast over your life by the mistaken belief that Korean cars are "reliable"- if the dealer can't fix it, look for someone else- but much easier to sell your Hyundai or trade it in on something with a reputation for reliability- come on, now- would you feel better owning something called a "Hyundai' or something called a "Ford"?

What does the dealer say each time you take it in? I would be a cheap ODBII code reader and see what codes the car is giving off when the check engine light turns on. On the other hand jamnblues might be partily correct meaning your car might fall into the lemon law and be a defective product as long as its still under factory warranty.

The dealer has replaced code P0071 ambient sensor 4X and codes P0140, P036 oxygen sensor 1X. The same codes keep coming on...they don't know why. ????

Short answer is trade it in. Kia and Hyundai are both made the same. Had this problem the entire time i owned mine. The only way I got rid of it was by trading it in on a jeep.

I have noticed sometimes I have left my vehicle started while filling up at the gas station. The check engine light will come on. The oxygen sensor will detect. To correct the check engine light. I disconnect the battery cables for a half of an hour. The check engine light will go off.