Mine is going back in tomorrow, Germany have analysed the data and it seems the actual error reported was turbo air intake temperature too high (although they seem to think this is a false reading).

The dealer says there are 2 electric pumps that pump the water around the air intake cooling system, via the intercoolers I presume, they now need to check the wiring and resistance of the sensors which are apparently in the pumps.

No sign of the warning today