UK-POLOS.NET - THE VW Polo Forum

I had the same issue a few years ago, turns out the drivers locking mechanism was leaking air where the vacuum hose from the pump plugs into. have a go at pushing the connector on hard whilst unlocking and locking the car to see in the door pins move. Try to avoid letting the pump run as it'll burn the motor out ( you may notice it gets very hot).

If this is the fault i have a nearly new locking mechanism available

Joe