These trucks also suffer with corrosion on the multiplugs on the controllers, sometimes you cannot even see the corrosion they just get enough of a film of corrosion on the pins to cause issues and throw multipul codes. The problem is the plug terms are aluminium and the pins are steel, so being dissimilar metals they corrode. Try some electrical cleaner and push the plug in and out a number of times to clean.
We quite often replace the terminals in the plug if they are to bad. You can get them from TVH, let me know if you need the part no.