I have about 112k on my XFI and the throttle body was cleaned in the last 6 months by the dealer. About 30k ago, I also had a split weld on the driver side cat which was replaced under warranty.

This morning, I got a P2096 to indicate the downstream was 1/2 lean. From what everyone has seen, whats the likelihood this is a fail(ing) sensor and not a cat going bad? Also, Autozone couldnt tell me which sensor was triggering the fault. Is it obvious when visually examining the sensor when its bad, or should there be a way for the OBD to indicate?

TIA!