Peugeot 308 Heating Issue

That sounds frustrating. The defrost air distribution flap controls where the air flows in your HVAC system, so if it's not working correctly, it can definitely impact heating performance. A defective cable or plug connection to the flap motor is indeed a likely culprit, given the error code. Have you checked the relevant fuses? Sometimes it's just a blown fuse causing the issue. Before diving deeper, confirming the fuses are intact is always a good first step.

Good shout on the fuses, I'll check those. But if the fuses are fine, how involved is it to actually get to the flap and check the wiring? Is it buried deep in the dashboard panel?

If the fuses are intact, accessing the flap motor and its wiring can indeed be a bit involved. It's often located behind the dashboard panel, near the heater core. Depending on the 308's design, some disassembly might be required. Given the potential complexity and the error codes pointing to a specific issue, I would strongly recommend a workshop visit. A diagnostic tool can pinpoint the fault and guide repairs. It is a relatively minor repair, which should be around 95€.

Thanks for the advice. Fuses were fine, so I took it to the workshop. Turned out to be a dodgy connector as suspected. 95€ later and the heating is blasting again.