Not a huge deal. It's a post-cat O2 sensor so it is primarily there for keeping the catalytic converter in check, it also plays a part in the A/F ratio, but not to the extent that the pre-cat sensors do.
The heater element basically makes the sensor warm up faster to get you out of open loop(closed loop is more efficient). I can't remember how many O2 sensors are under a TJ in all, but if it's 4(as opposed to 2), then check your PDC as there should be an O2 sensor heater relay, which supplies the voltage to the 1/2 and 2/2 O2 sensors heater elements. The 1/1 and 2/1 sensors get it directly from the ASD(auto-shutdown) relay. All are PCM triggered, but I doubt the PCM could be the problem as it's only the 2/2 sensor throwing the code, I'm not positive but I believe both the post-cat O2 sensors are on the same circuit so aside from the O2 sensor itself going bad, it could be the wiring.
In a nutshell:
A) Check the O2 sensor wiring for any opens, shorts, etc anything visually wrong with it.
B) Replace the 2/2 O2 sensor(bank 2 sensor 2).
You may find your gas mileage takes a crap until it is fixed.