Recently I decided to delve into finding the root of the problem to my non-op central locking system. The purpose of this thread is to bring together the information I found myself and from searching the web for a few hours. In the hopes that whoever has this issue next will be able to find this post useful therefore I will attempt to make it as clear as possible hopefully with pictures to follow in the future. Ill attempt to post this to most of the forums.

NOTE I AM NOT A PROFESIONAL IN ANY WAY, I AM SIMPLY CONVEYING MY PERSONAL EXPERIENCE WITH THE ISSUE.

First off here were the symptoms;

• Central locks didn’t work (duh)
  
• Key fob works
  
• Alarm could be set (with key or key fob) however locks would not actuate.
  
• Motor could still be heard running when lock or unlock button pressed.

My simple solution to this problem at the time was to manually use the locks and to manual (key) lock my door. However this started to become a hassle and an embarrassing one at that. So I decided to start hunting it down.

• First I checked the obvious culprits;
  
• Fuse (because it’s the easiest and doesn’t hurt to check)
  
• Vacuum leaks. (On a previous car I could hear the vacuum hiss so I circled the car while listening intently)

Finally after check those and walking around my car on the side of the street rather sketchily. I popped the boot and started digging.

• The Central locking unit is located on the right hand side directly beneath and behind where the taillight would be.
  
• You will have to remove a few of the carpet fasteners located right near the seam between the trunk lid and where the side wall carpet starts. Also remove a few of the screws on the plastic sheath that is the bottom edge of the trunk opening (this will make it easier to pull carpet).
  
• Pull back the side wall carpet well enough that you can get in there comfortably.
  
• At the bottom corner you will see a block of squishy foam, Pull this back and you will see a rectangular box with a cylindrical section protruding from it. Find the two vacuum lines entering the unit and grab the white rings and squeeze as you pull them back this should get them off.
  
• There will also be three plugs attached to the unit. Remove all three in order (the only order you can easily remove them) from smallest plug to largest. !Not the orientation of the last large plug ( I replaced it backwards and it seemed to turn my front and side running lights on as well as disabling the alarm system)
  
• Once the vacuum lines are removed along with the plugs you can remove the box.
  
• It will take some squeezing or a flat head screwdriver to pop the top cover off there should be 8 or so points you will need to release before getting it off.
  
• After taking the lid off you will see the circuit board gently pull this away until the contents of the box is visible.
  
• You may notice a large amount of black "soot" looking stuff everywhere. IF SO then you have the identical problem as I did.
  
• Looking into the box there will be a black disk shape object on the side with the cylindrical protrusion. With three screws.
  
• Carefully remove these three screws as well as the black plate (graphite) after removing this there shall be a graphite ring whilst in the middle will be the motor drive with a black graphite disk with sort of cross cut into it this is the impeller (I am unsure what this is actually supposed to look like as mine was utterly disintegrated when I opened it)

IF THIS IMPELLAR IS STILL INTACT ALONG WITH THE SMALL DRIVE GEAR IN THE MIDDLE AS WELL AS LOOKING CLEARLY FUNCTIONAL. STOP READING as the rest of this post is purely to deal with resolving THIS issue.

Now with the graphite impeller destroyed you have a few options;

• You can go to the Audi dealership (or online sources) and buy a new unit. However the unit available isn’t just the broken pump or impeller but the entire boxed unit. Which as I found out today after visiting my local dealer is approximately 475$ Suffice to say not a very enticing solution as you will also have to pay to have the new unit installed and coded which will cost around 600-800$ when everything is said and done.
  
• Your next option is to buy a refurbish kit online. On my searches I found one good source and he wanted about 85$ Canadian for the unit plus shipping from the u.k Once again a bit pricey depending on your budget but much better than the previous.
  
• Your third option is to go to your local scrap yard and find a like model Audi or even near year Passat ( preferably the Passat as the impeller unit is a bit beefier then the Audi one thusly avoiding the possibility of shattering another one) While also making sure this unit does not have the same problem.
• This will cost you less than the previous option. By how much I can’t say as it varies from yard to yard.
• However be sure to take out only the electric pump and impeller unit along with the black retainer that has a small tube going to another part of the box to direct the vacuum.
• This is removed by pulling on the black rubber nipples (for lack of a better word) from the inside, while pushing the same nipples into the whole with a fine screwdriver or prod from the other side.
• Doing this will save you more money as the rest of the unit will be useless unless you plan to buy the whole thing and have this recoded (which is a cheaper way to go about step one)
  
• Once you have gathered your parts. Option one can be done at home by installing the new unit however you will need it recoded and I haven’t the foggiest how to do that therefore I would suggest a professional unless you know how to do it yourself.

Option two and three will be very similar from this point.

If you have a direct replacement from an Audi you can simply do the reverse of how you got them out However if you got the Passat version it will need some slight adjustments to the vacuum direction ring (as stated above once again for lack of a better name) This can be done by cutting a section out and replacing with rubber vacuum line to shorten the length.

After this is done and everything works put it back in its place re attach the vacuum lines and plugs then test your locks if it doesn’t work something may not have been attached properly if it does work, pack away the unit into its protective foam. Re place trunk interior and screws. And be once again pampered by the use of remote central locks

Hope this helps anyone in the future. There are a few other good sources out there but I though I would compile the information a bit here. I will attempt to add pictures if I can get a camera.

CHEERS!

Mike

 

Note I just went to the scrapyard yesterday and couldnt find one from either an A4 or passat so I actually got one out of a MKIII jetta ( golf will work to) This requires the same work as the passat pump. Some slight modifaction to the vaccum tube and you will need to splice the wires or re solder them. ! cost me 20$ I also attempted to grab the graphite plates off another pump to refurbish the original A4 pump however the backing plate has different vaccum locations so this is not possible without heavily modifying the graphite rings. Suggestion is to just get the whole pump unit and cut the vaccum supply line and adding in a peice of hose to make it reach the vaccum outtake lines