Accent weak heating water valve issue

Sounds like a classic case of a malfunctioning water valve. The error code pretty much confirms it. Have you checked the coolant level? A low coolant level could contribute to poor heating performance. Also, inspect the wiring and plug connector to the water valve itself. Look for corrosion or any signs of damage. Sometimes a simple cleaning of the contacts can resolve the issue. The water valve, also sometimes called a heater control valve, regulates the flow of engine coolant to the heater core. The heater core is essentially a small radiator located inside the passenger compartment that provides heat.

Thanks for the info! Coolant level is good, and I did give the connector a look-over – seemed okay at first glance, but I'll double-check for corrosion more closely. If the connector and wiring seem fine, is it pretty much guaranteed to be the valve itself?

If the coolant level is correct, and you've thoroughly inspected the wiring and connector to the water valve, and still have the error code and poor heating, then yes, it's highly likely the water valve itself is defective. Given the error code, it's best to visit a workshop for a proper diagnosis, since you have to measure the electrical current to be sure.

Thanks, I appreciate the confirmation! I went to the workshop today, and you were spot on. Turns out the water valve was indeed defective, just like you said. They replaced it, and the heating is back to normal. The final bill came to 95€, which was a relief. Thanks again for your help!