thanks for your reply marc, no error codes and it is only faulting when wheel at 90degrees, i looked at this truck a week ago and i believe the pointer on dash stayed in same position. it is not faulting every time unfortunately.

Hello Barney,
I've tried it on a truck we have in our stock, and it working all the time. Only if driving for example forward and changing the directional switch in forward the truck still drives forward you can only change by pushing backwards direction. Is this problem only happening when the steering wheel is at 90°? Can you tell me if the steering angle on the display is pointing correctly and if isn't giving any error messages. Could be that the switch for drive position detector is fault or well adjusted.
Kind regards