control panel screen failure

2019 AS Bourton on Mercedes running gear.
The Control Panel  with touch screen  has decided to not play. the affect is that the screen is like a piece of paper that the computer has printed with very little ink in the cartridges, this means i have no way of selecting any of the 12 V systems.
A code on the Truma control says W255 H  which indicates a wiring fault.
240 v  was being supplied at the time , all the lights etc were normal on the EC700.

Have any of you gentle folk experienced this, or has the 'Haunted Snail' lulled me into a sense of security in the last year ?
Off to the dealership tomorrow - again .

I haven't experienced this (yet) but have you tried turning the Truma off on its CP and then shutting down the EC700 PSU for a few minutes, and disconnecting the EHU for good measure, and then turning the EC700 PSU back on?

As Caraman says, turn the power off on the EC700 for a minute or two and then turn it on again, it should reboot the system.

Had something similar a couple of weeks ago and that worked for me.