Central Locking Problem

[Gary.Townend]

Hi everyone
I know that this subject has been covered before, but I am a complete novice when it comes to anything vehicular.
My 1998 A4 Avante 1.8SE Estate has developed a problem with it's central locking.
Everything was working fine, all doors locking, lights flashing and alarm activating, until last week.
Now the pump makes a noise, but doesn't open or lock the doors. I can lock the doors using the key on either drivers or passengers doors, but this does not lock the boot or other doors. The alarm does trip when you open the boot.
I have removed the unit and the hoses but the unit seem to have minimal amount of suction. I have removed the unit and it is as dry as a bone.
Now I have started to source replacement units on the internet, but now I have another question.
If I replace the unit with one with the same number do I have to recode my key, and if so is this something I can do myself.
Any suggestions would be greatly appreciated.
Thanks in advance

[Sly]

Hi, it's well worth doing a fault code read before you go much further. I've just seen a pump impeller repair kit on ebay item number 140526182452, don't know how good these are though.

If you end up changing the whole unit, I might be interested in the old one, I want a relay out of it for my boot light but don't want to spend loads on a whole unit to get one. Hope it turns out to be something simple for you though.

Good luck...

[mikeybutch]

Had this on a B5 Avant a few years ago and found a repairer who said the impeller blades are plastic and not robust so he replaced with one from a Merc and it worked fine until car was sold a year later.I dont think that it takes much suction and you sb able to operate the locking by mouth if the piping isnt brocken .If there is abreak you may be able to hear a leak but I gave up and accepted that the blades has imploded