Celica Air Distribution Flap Error

Hmm, interesting. You say 'air distribution flap'. Is that the one behind the dashboard panel that directs air to the vents (defrost, feet, face)? Because if that's malfunctioning, it would definitely mess with your heating. I imagine if it's stuck in one position, it wouldn't matter how hot the heater core is getting. Have you checked the linkage to the flap motor itself? Maybe it's disconnected or binding somehow?

Yeah, that's the one. The flap behind the dashboard. I haven't dug into the linkage itself, mostly because I'm not entirely sure where to start poking around. Is it accessible without pulling the entire dash apart? I'm trying to avoid that if possible.

Okay, understood. It’s notoriously difficult to get to! While you might be able to access some of it, really getting in there to properly diagnose a broken linkage or a faulty motor without a full disassembly is... optimistic, to say the least. And because you've already found a stored error code, you should expect more than just a loose connection. I'm sorry to say that based on the age of your car, a trip to a workshop could be unavoidable, especially knowing it could be a defective flap actuator. Do you have any resources for diagnostics?

Thanks. I was hoping to avoid that. But, fair enough. A local shop ran diagnostics and confirmed a faulty connection. Total cost was 95€; that was way cheaper than replacing that air distribution flap!