Why can't I open metal flap cover for access to petrol cap?

I think the system on that car enables you to open the petrol flap once the drivers door is unlocked (either by pulling the cap open or pressing on the flap).

1. Lock the car using the central locking.
2. Insert the key on the drivers door, turn it once and unlock it. Open the door to check you have unlocked it. Then turn the key in the lock again as if you were unlocking it a 2nd time.
3. Now open the petrol flap as the lock should have released.

I'd try to have someone help push the fuel flap, (cover) and you try to carefully pry open the cover. It may require multiple hard push on the button. Issue could be lubrication bent, misaligned catch, electrical button, or wiring connections. Possible vandalism. If you get it open, leave it open until you can get it fixed. Warranty? Google your problem, you may find others have same problem and have a "fix" for it.

The petrol flap doesn't have a lever to open it like other cars but can be opened when the car is unlocked by pushing on one side of the flap to open, if this will not open then the fuel flap locking actuator is faulty and has not unlocked the fuel flap, if this has occurred open the boot and on the left hand side of the boot you will see a round button, if you cannot see this and you only see a hole then chances are the side cover has been off at some stage and the button hasn't been reinstated, if it is there, pull on it and it will pull the fuel flap locking actuator back allowing you to open the fuel flap.

you may have to get into the boot and remove any trim to the filler tube area. This will give you access to the flap lock system that holds the door closed . If there is a solenoid there you may be able to manually pull the rod that releases the flap lock or move the whole thing to let the flap open

Take it to a mechanic.

Hello Alan,

I would suspect the fuel flap actuator has failed. Open the trunk. In the right rear corner is the access cover. Open it and you'll see some insulation matting near the top. Behind it is a fuse/relay carrier, I believe either fuse 55 or 56 is blown. If so the fuel flap actuator needs replaced. The fuse also controls the central locking system.

Sounds like the solenoid is defective, but the petrol cap can be opened by opening the boot and putting your hand down the side of the back panel (petrol cap side). You should be able to feel the solenoid and on the back there is a lever that can be pulled out which will release the petrol cap latch.

Look for an Emergency Realice in Trunk

it is possible to find it in the glove box as well

NO CAR year TOLD AT ALL HYJACKER. TO 2009 AND SAME PROBLEM WITH lJBDJ
\Chevrolet TrailBlazer
some cars have FLAP that only protects fill nozzle from cracking
body paint. so is not at all part of EVAP
buy a new cap.
if still fails buy the tank filler assembly from chevy, parts.
nobody can see your flap , no posted photo of it,
and matters hug.