In the analyzer menu, centre pot to zero counts, make sure the pot is centred, there can b a deadband at the end of a rotation, the pot is still not centred, turn pot if value changes smoothly, in both directions, then that is middle.
Best place for a TVH pot is the nearest bin.
Have you tried calling your TVH Dealer for assistance?
Also could be the pot itself I have had pots bad out of the box and this is more common in my experience with aftermarket pots and encoders. I always stay OEM with these parts nowadays.
Do you have your pot zeroed 180 deg out? Some pots have a stop in them and some do not. The pots that do not have a stop will have two points of zero. If you are set up on the wrong zero the machine will fault out. The counts are how the access controller gets the command from the pot like an encoder. You should be able to see that through your access 1 in service access analyzer. Are you getting a fault code when it fails?