When your Truma heating    ” wont work , have tried everything , Manual useless, Truma helpline not available  , try this:

For future reference turn off the truma and wait 20 mins – it then resets itself.
Make sure you turn off at the control before disconnecting gas or electricity otherwise the error code will come on again.

The system has its own close down cycle and if you just un hooked the mains with it still set , this code comes up. In Truma theory it ie the gas supply interrupted , but if you have gas supply , then try this before despair sets in.