Work and car relief for vixmom!
I don't understand (well, duh, who does?) about the check engine light. They connect their computer and it gives the reason code that the light came on. So is that "reason" not checking out to be any problem, and the light stays on, or it comes back on after they turn it off? Is the car at a Hyundai dealer?
A couple of years ago mine was coming on intermittently, with the reason code pointing to the catalytic converter. I'd been taking the car to my nearby Firestone for a while, and they told me it was time to replace the CC (I think they quoted $1300), but that it could be put off for a while, at least until time for an emissions test. And of course I put it off. Then a while later I was at the dealer for something unrelated that I wanted them to handle, and one of the "small" things they replaced was a hose clamp or some such on the exhaust system. Guess what? No more engine light, and the car passed its emissions check months later. Which it thankfully has always done anyway, but this time it was an extra special relief.
On the other hand (unfortunately, there's always an other hand), it took that dealer... how many visits to find the air conditioner leak a few months back? Oy!
So, not that any of this helps vixdad's Elantra!