Have had a MIL/CEL indicator pop up intermittently over the past few months. DTC code indicates the NOx Sensor #2 is faulty. Before I could get to replacing it, the indicator went off. It has come back on, then gone away a few times since then. I logged the real-time data from it a couple of times while driving, both during the malfunction mode, and in normal mode, and can't really tell much difference, if any. I don't even know what the normal range is, it fluctuates widely, depending on throttle setting, etc. (But so does the NOx #1 output).
Anyway, Rock Auto has an OEM GM part for about half of what the parts stores are priced. I was just about to buy it, but noticed on the specs it says "Programming Required - Yes".
Is this true? And if yes, is it something only a Dealer can do, or would an independent Diesel shop be able to program it?

Thanks in advance for any info. or advice.