Fault Code 3749 on ISX15 2350

[Golfnut]

I've been hauling beans from the field to the elevator the past few days and late this afternoon I got a check engine light on my dash. I had my laptop and NEXIQ with me so I plugged in and the code was 3749. I reset it but the light came on again within 20 miles. The code states that the Aftertreatment NOX Sensor Not Rational - Drifted High.

What is the process here? Do I simply replace the sensor?

Truck has 329,000 miles. In the past 5,000 miles I've replaced the Delta-P, IMAP, and Exhaust Gas Pressure sensor. I also inspected the doser and it appeared clean.