.05 OCTAVIA MkII ELEGANCE TDI PD DSG HATCHBACK,

Fuel filler flap/door won't lock.

The Actuator will unlock (rod wthdraws) if the the rod is extended but won't extend (to lock state) by key fob remote

I have swapped Fuel Filler Door Actuator (1Z0810773 picture below) but no change.

Actuator consists of an electric motor which moves locking rod in and out via worm screw wth no apparent mechanism to reverse the motor

As there are only 2 wires to the Actuator,

My guess is the locking action must involve a reversal of applied voltage to make the motor push the rod out, problem is i don't know how it is done.

Does anyone have any ideas?

 

 

Can you replicate this behaviour with someone inside the car using the lock button by the handbrake?

 

18 year old electronics!

 

Have you had any weak battery/hard start events?  I ask as a momentary drop in power to certain electronics beyond what they need can cause system corruption and weird behaviour.  In that case a battery charge and disconnect to reset the car's electronics can work wonders, the key is having a healthy electric supply to prevent electronic brown outs when starting the engine.

 

Don't condemn a battery prematurely, on a car of such vintage check all relevant wiring, connections and alternator output first.