Technical Glow Plug Error

[radon]

Hi, My Eldiss Motorhome on a Ducato Chassis 2022 140 Multijet Euro 6 Engine displays a flashing glow plug light.
A diagnostic scan (Multiecuscan) shows DTC P0683-13 Preheating control unit (feedback) Open circuit.
All I can find at the moment is 3 heater plugs cold resistance of 1 ohm and 1 heater plug at 0.6 ohms.
All those resistances seem within spec but I don't understand why one should be so different.
The van has only done 3000 miles. no problem starting and plenty of power.
I don't think heater plugs come under the warranty.
Need some advice please.

 

[radon]

Hi, I have just noticed today after doing some more diagnostics, laptop plugged in and ignition on I reset the P0683-13 DTC and it immediately comes back, at this point the heater plug relay would not of energised as the ignition was always on so no supply to heater plugs. so its starting to look like a communication fault ?