Hyundai Repair: Check engine light and codes, oxygen sensor, warranty service

Question
My check engine light just came on, i also just failed because of emmisions durring inspection. the code that came up is P2096. My car is a 2004 Accent. Could you tell me what the code means. Thanks

Answer
I've not seen this code occur before.  It means that the rear oxygen sensor value is lower than the engine computer expects it should be.  

I'd primarily suspect either a skewed front or rear oxygen sensor, but the problem could be caused by an exhaust leak or faulty catalytic converter as well, according to the shop manual.

It you're under 60,000 miles, take it in to the dealer for warranty service and let them figure it out.  Based on the code definition, this could be difficult to diagnose.