Avantime Auxiliary Heater Fault

I had a similar issue with my Avantime's auxiliary heater last winter. Check the temperature sensor that sends info to the climate control unit. A bad reading can stop the heater from starting, even if the glow plug is fine. Is your ventilation system working normally?

Thanks for the tip! Where is that temp sensor located, and how easy is it to test? The ventilation seems okay, blowing hot and cold as it should. Could a bad sensor really stop the heater, even with a fault code?

Yes, a faulty temperature sensor can absolutely disable the auxiliary heater, even with a stored fault code. It's part of the climate control safety logic. Finding the exact sensor location on the Avantime is a pain, and testing it properly requires specialized tools. I took mine to a workshop. They diagnosed the glow plug and the sensor, and that fixed the problem.

Okay, thanks so much! Sounds like a trip to the workshop is inevitable. I was hoping to avoid it, but at least I have a better idea of what to expect. The bill came to 440€, glow plug and sensor replaced. Thanks again!