Hi,
I purchased a odb reader so I could check the errors on my 2018 GLC350d Bluetech as the mpg dropped 30%. First tought was to do a DPF regen as the exhaust dpf could be the culprit. However, I get an error saying that the engine temperature is -273 and dpf cannot be done.
I also notice that the engine seems to run as if cold all the time i.e. idling about 200rpm higher than normal.
So I figure that a temp sensor is at fault here.
Has anyone had the same issue and could let me know which sensor might be at fault.

Thanks