C1 Low Heating Output

Low heating output and an error code certainly point towards a cooling system issue. Have you checked the engine coolant level recently? A low coolant level could indicate a leak, which can affect the heater core's ability to provide adequate heat. Also, inspect the hoses connected to the heater core for any signs of blockage or damage. A blockage could restrict coolant flow, resulting in poor heating performance.

Thanks for the quick reply. Coolant level seems fine, no visible leaks. Where exactly is the water valve located, and is it difficult to access on the C1?

The water valve on the 2022 C1 is typically located near the engine block, often in close proximity to the thermostat housing. Access can be somewhat restricted depending on the specific engine configuration. Given the error code and your symptoms, it's likely that the valve itself is malfunctioning or that the cable/plug connection to the valve is defective, as per the error memory. I'd recommend having a workshop diagnose this further. The valve might be stuck or the electrical connection could be faulty. Replacing the valve and ensuring proper connection should resolve the issue.

Thanks, I appreciate the detailed info. Took it to a workshop; they confirmed it was the water valve and replaced it. Total cost was 95€. Heating is working fine now.