Spoke to the dealer today and VGA has finally admitted that a wire might have been damaged as part of the tow bar and brake controller installation. So now they need to get all the wiring tested to find the fault. I asked them to isolate the brake controller but they can't do that without uninstalling the whole unit. Even if they uninstall the tow bar and brake controller, the damaged wire could still exist in the can bus wiring itself. So at this point, it looks like the fault was with the installation and had nothing to do with recoding. Let's see what they come back with in the next couple of days.