Originally Posted by Lord Vader
Welcome to Bimmerwerkz.
As part of the central locking system the gas door will lock as well to prevent gas theft or tampering. Each door locks from a device called the actuator. The actuator converts an electronic signal from the Central Locking Module into a mechanical action (locking or unlocking). Overtime these actuators will start to fail. Causes vary as to why, but they have components that wear out. If all the doors lock/unlock fine but the gas door doesnt then you should replace the actuator. Using a voltmeter make sure you have power going to it first.
Thats for ur info. Doors and gas door actuators all work is just that gas door stays open so when gas door actuator activates, it does catch door. I was looking at door n it has something that i guess it works as a spring to keep door close and prob worn or lost its tension. But not an expert just guessing.