If your vehicle is showing fuel filler door won't open, here are the most likely causes and the parts you'll need to fix each one.
Dirt, debris, rust, or freezing temperatures can cause the fuel door hinge or the locking pin to bind, preventing the door from popping open even when released.
On vehicles where the fuel door is tied to the central locking system or an electronic button, the small electric motor (actuator) that retracts the locking pin can burn out or seize.
For vehicles with a mechanical floor lever, the steel cable connecting the lever to the fuel door latch can stretch over time, snap, or detach from its mounting points.
A small metal leaf spring is usually responsible for physically pushing the door open once the latch is released. If this spring falls out or loses tension, the door will unlatch but won't pop open.
An electrical short or a failing actuator can blow the fuse responsible for the electronic fuel door release circuit, cutting power to the release mechanism.