NOX code P2201

[CFrance]

Hi all,
Got a P2201 code showing NOX sensor #1 bad. Crawled under truck and I can only find the downstream sensor. I was told there were 2 sensors, an upstream and a downstream. I cannot find the upstream sensor. Is there 1 or 2?
Thanks in advance for your help. The truck is a 2014 3500 6.7. The SCR was replaced last year.
UPDATE: Found it, it is right below the turbo.

 

[Bob4x4]

The module bolts to the block,follow the wires to the sensor.The module comes with the sensor-do not try to separate them