Resolving problems with the hot-water auxiliary heater
FAIL appears on the remote control display 
Possible cause:
Signal transmission between transmitter and receiver is malfunctioning.
Change your position in relation to the vehicle, moving closer if necessary.
FAIL appears on the remote control display
Possible cause:
The starter battery is not sufficiently charged.
Charge the starter battery.
Possible cause:
The fuel tank is not filled up to the reserve level.
Refuel at the nearest filling station.
FAIL appears on the remote control display 
Possible cause:
The auxiliary heating has malfunctioned.
Have the auxiliary heating checked at a qualified specialist workshop.