Karoq Diesel Heating Problems

Low heating output and an error code definitely point to a problem in the cooling system. A defective water valve is plausible. Have you checked the coolant level? Is the engine overheating? Sometimes a valve blockage can also restrict flow to the heater core.

Coolant level seems fine, and the engine temp is normal. When you mention valve blockage, is that something I can check myself, or is it best left to a mechanic? Don't want to make things worse!

Given the error code and your symptoms, it's likely the water valve itself or its connection. While you could try checking the connections, it's a bit fiddly and requires some knowledge. A valve blockage is less likely if the coolant level is stable and the engine isn't overheating. I'd suggest getting it checked by a workshop. The 95€ estimate sounds reasonable.

I booked it in, and they confirmed it was the water valve. The bill came to 95€ which I was expecting. Seems the cable connection was indeed faulty as suspected. Thanks again for your help!