GM DPS Add Vehicle Feature

I have a 2024 GMC Sierra 2500 HD with a diesel engine. I’d like to add the fast idle feature (RPO UF3). All hardware is factory installed. It only needs to be activated. I took it to a dealer and they had trouble installing it. I have an appointment with another dealer next week to try again. 

I’d like to try programming it myself. I bought a VCX Nano and installed the DPS and GDS software. I can communicate with my truck. The ECU Configuration option is greyed out. I assume it’s due to Global B. I found someone on here that can help get around the Global B problem. 

The big problem is the RPO code. Where do I get that?  How about the XML file? Is it necessary? Are the RPO options for my VIN listed in the XML file?

I have a 2024 GMC Sierra 2500 HD with a diesel engine. I’d like to add the fast idle feature (RPO UF3). All hardware is factory installed. It only needs to be activated. I took it to a dealer and they had trouble installing it. I have an appointment with another dealer next week to try again. 

I’d like to try programming it myself. I bought a VCX Nano and installed the DPS and GDS software. I can communicate with my truck. The ECU Configuration option is greyed out. I assume it’s due to Global B. I found someone on here that can help get around the Global B problem. 

The big problem is the RPO code. Where do I get that?  How about the XML file? Is it necessary? Are the RPO options for my VIN listed in the XML file?

If you've never used dps before I wouldn't suggest you messing with your 80k truck. Also you need oem MDi2 or anything that supports canFD,  vcx nano will definitely not work.