GLC Diesel Rough Cold Starts and PTC Heater Code

I had similar symptoms with my older BMW, although it was a petrol engine Rough cold starts, poor running until warmed up The blower motor seemed to be running at full speed constantly Have you checked the wiring harness and connector to the PTC heater Could be a corroded connection causing the issue rather than the heating element itself

Thanks for the quick reply I did a quick visual inspection of the connector, but didn't see anything obvious like corrosion or damaged wires I'll take a closer look at the wiring harness this weekend Did your BMW throw a specific error code related to the auxiliary heater, or was it more generic

Yes, there was a specific code for the auxiliary heater electrical fault I'd suggest getting a proper diagnostic scan done, beyond just reading the generic codes If you're not seeing anything obvious with the wiring, it might be time to get it checked by a workshop

Thanks for confirming I double-checked the wiring again as you suggested, and still found nothing Ended up taking it to a workshop and they confirmed it was indeed the PTC heater 360€ later, it's running perfectly again Appreciate the advice