Limp Mode While Towing

[MillerMav]

Hey everyone, hoping to get some help. I have a 2013 X5, full deletes, Malone tune and Rod Sutphin trans tune. Normal driving conditions it runs great in all situations. I installed all the tow equipment last summer and had Bradley Tourt do all the coding. All is well there. I have pulled a few smaller items with no issue in the past. I recently bought a new camper and the current weight is around 6000lbs. I have a weight distribution hitch on because the tongue weight of 510 is a little light and I wanted to have a bit more sway control as well.

Anyway on to the problem.....as I said, without towing the camper the X5 runs great, pulls hard, no issues at all. When towing the camper no matter if I accelerate quickly or slowly the vehicle goes into limp mode at 65mph exactly. I tested it 3 times this afternoon. First time normal acceleration - failed, 2nd soft acceleration - failed, 3rd hard acceleration - failed. Everytime at 65mph. I pulled codes with my fox well scanner NT510 and this is what I have:

A1 03/Not Present - CAS immobilizer bus fault
2E3D/present - DDE interface EWS-DDE
2E41/not present - DDE interface EWS-DDE
428B/present - DDE boost pressure control low-pressure stage, control deviation
CF37/present - Message from car access system to body bus faulty. receiver EGS, transmitter car access system

Could it be that the camper is simply too heavy? Any help would be appreciated. I have about 6 weeks to either figure out the issue or get a different tow vehicle before our first tripped is planned for memorial weekend. Thanks everyone.