Latitude low heating output

I had a similar issue with my old BMW 3 Series, though not exactly the same car. The heating was weak, and it turned out to be a blockage in the heater core. Have you checked for coolant leaks or considered a valve blockage in your cooling system?

Thanks for the suggestion. I haven't noticed any coolant leaks, but how would I specifically check for a valve blockage on the Renault Latitude?

On my BMW, the mechanic used a pressure test to check for leaks and inspected the coolant flow. Honestly, given it's a potential cooling system issue and you already have an error code, it might be worth getting it checked by a workshop. They'll be able to diagnose it properly.

Thanks, I appreciate the advice. I took it to a local mechanic, and you were right – it was a defective water valve. They replaced it for 95€. Now the heating works perfectly again!