4Runner fuel flap release malfunction

That sounds similar to what I dealt with on my old Volvo C70. The central locking actuator went bad, affecting not just the fuel flap but also other systems. Have you checked the actuator or the wiring harness going to it? Sometimes a corroded connector can cause similar symptoms.

When you mention the central locking actuator, are you referring to the part that directly controls the fuel flap release, or a more general module? I'm trying to figure out where it is and what it does so I can inspect it.

In my case, the Volvo used a central module that controlled several functions, including the fuel flap. A fault there cascaded to other systems. Given the symptoms and the error code, and if you're sure the linkage is intact, it's best to have a workshop run a diagnostic to pinpoint the fault before replacing parts at random.

I appreciate the guidance. I'll get a professional diagnostic. The repair cost for the defective linkage was 210€.