After changing the pump at a scrappy for a fiver (of which there are 2 types i believe) it didn't work straight away. Only a few doors worked or it was very slow etc. It took me a day to re-pressurise the locking by opening and closing the locks.
One thing which was very odd though was after a good while of doing this, the motor stayed on for about 2-3 minutes !!!! I thought something was wrong, but it appeared to work ok after that !