GLK Diesel Cold Start Issues and Fuel Consumption

Ugh, that sounds familiar! I had a similar problem with my old Renault Megane. The heating system acted up, and it turned out to be a defective auxiliary heater, too. Seriously annoying! Was the same error code stored in the memory?

Yeah, the error code definitely points to the PTC heater. What exactly did you experience with your Renault? Was it just cold air from the blower motor, or did it also affect the engine's performance during cold starts?

With the Megane, the cold air was unbearable. And yes, the engine was sluggish during the initial phase until it reached optimal temperature. I'd say take it to a workshop, it's probably the PTC heater and it's better to have it professionally diagnosed than fiddling around with it yourself.

Thanks, I appreciate the feedback. I took it to the shop, and you were right – it was the PTC heater. Repair cost came out to around 350€, but now the engine runs smoothly from the start and the fuel consumption is back to normal. Thanks again!