Prodemand's information on the GEM module for your truck is contained in the attached images. The way I read it, the module must be programmed either way. AllData says the same thing.
Neither specifies exactly what happens if you do not have it programmed, so I would just err on the side of caution and get it properly done.
Images (Click to enlarge)
Monday, December 3rd, 2018 AT 4:10 AM