XC90 Diesel Cold Start Issue

I had similar symptoms with my old Mercedes C-Class. Cold starts were rough, and fuel economy took a hit. In my case, the mechanic suspected the temperature control system. Did you check the heating element for any damage? The blower motor could also be a suspect, maybe?

You mentioned the temperature control system. Could you elaborate on what aspects were relevant in your case? I am also curious if an electrical fault could be the root cause.

Certainly. In my Mercedes, the diagnostic pointed to a failure within the PTC heater circuit, eventually leading to the replacement of the auxiliary heater. Given your symptoms and the error codes, it's possible the auxiliary heater in your Volvo is failing. It's best to get the heating system checked thoroughly. I would visit the workshop.

Thanks for sharing your experience. It seems a defective electric auxiliary heater is indeed the likely culprit. The repair cost is estimated at 350€. I will proceed with the repair as suggested.