2014 Pete 386

[Casper]

Took a look at the 386, after driving and looking it over, it threw up a fault code 3216. Shop replaced the NOx sensor, did a re-gen and code disappeared. They replaced a couple of tires (my request...they had a flat spot, causing a little vibration)....drove it again, purchased it and left...drove several hours, parked the truck for the night. Cranked this morning, drove a couple of hours and the fault code popped up again....after reading through all the forums here, I'm guessing it's another bad sensor OR..it wasn't installed properly....working on that right now! Any input??