522633-2 = Pre-Cat Bank 2 Sensor Fails To Switch To Rich
This is an O2 sensor fault
It would be beneficial if you could access the onboard diagnostic so you could see it in action (or inaction) but if the code does not allow you access chances are it has been changed by the dealership.
All in all the 02 sensor may be faulty, OR check the plug where it connects to the harness and inspect the wiring and connections. These have been known to get damaged.
If i'm not mistaken bank 1 is the left hand side sensor (pre catalytic) and bank 2 is the RH sensor (post catalytic).
Translation: bank1 is before it enters the catalytic converter, bank 2 is after it exits the catalytic converter. ;o)
So go to the rear of the truck, look at the muffler, pipe coming in from engine is one 02 sensor (pre-cat) and then the tail pipe coming out of the muffler (post-cat).
They do this to measure the emmissions before and after to help the engine adjust air/fuel mixing with the ecm.