Accord Hybrid

My 05' Honda Accord Hybrid IMA light came on...Dealer says...?

Car has 42,000 miles. I just bought the car less than 30 days ago. The IMA and check engine light came on the other day so I took it to the dealer I bought it from. His mechanic looked at it and said the O2 sensor was bad and would need replaced. He said that the hybrid battery charger wasn't working right and made it dirty.The mechanic wasn't familiar with hybrids so he said to drive it to a Honda dealer to get it all fixed. What could be causing the 02 sensor to get dirty? The dealer only offers powertrain warranty. Is there a warranty still on the car that Honda would pick up? Is powertrain even considered to be part of the hybrid part of the car? Any help with this would be great.

Thanks!

The guy is full of ****, its not an 02 sensor I can guarantee that. It wouldnt have anything to do with charging the battery. You need to have the OBD2 system scanned by the dealer to find what codes the computer has stored. IMA isnt a familiar code ive ever seen, probably related to the hybrid drive.