Hyundai Repair: Code #, oxygen sensor, trouble code

Question
What does Code 2251 mean?

Answer
Hi, Barbara.  I'm going to presume you're referring to engine trouble code P2251.  This indicates there's an open circuit in the ground for the upstream oxygen sensor.  Usually, the open circuit is within the oxygen sensor itself.

While I've seen this code before, it's rare.  I'd feel better if I knew the year and model of your vehicle, as this code is not valid on all vehicles.