Hi.
I have an A4B5 estate, year 2000, 2.5tdi. I have done a quick search on here but have not seen a post relating to the specific problem.
It started just after Christmas when I noticed the rear hatch was showing open on the dash display. I got out and closed it, only for it to open again. Then I noticed the mechanism was operating uncommanded continuously. So I shut it again and turned the key to the horizontal locked position to keep it shut. At this point my three buttoned remote key worked.....then it didn't. Ever since, I have had to use the key manually to get into the car. however, it does not open all the doors until the ignition is switched on. If there is a delay in unlocking the car and switching on the ignition, the hazard lights come on, allbeit a little fast. But these switch off once the ignition is switch on.
I have tried one method of re-syncronizing the remote central locking but to no avail. I do not hold out much hope for the other method of using two keys, one in the ignition, the other in the boot.
Any suggestions as to where I should start to look for my problem? I have read that the tailgate lock needs to be replaced but that still leaves the remote central locking problem.

 

Start by looking for water in the well where the central locking pump is. It's in the right rear of the trunk. Lot's of guys get water in there, and it frys the system.

 

I have checked that and it's dry, or seems to be. I tried re-syncronizing both keys this evening using one key in the ignition and one in the door, but to no avail onn either key. I will replace both batteries tomorrow and try again. There is another Audi in the breakers yard not far from where I work. I will see how much they want for the module out of that.
Meanwhile, any other suggestions.......?

 

Yea, before you throw more money at this problem, you really need to VAG-COM it to see what's going on. We're really spit-balling her.

 

Fixed the central locking problems from the key fob. Car seems to be leading me on a wild goose chase. First the tailgate lock went AWOL then a day later the remote controls did not work from either key. So naturally I thought the problems were related.
Turns out both key fobs batteries were discharged, so replacement batteries fitted, re-sycronised the keys and all is well. However, the tailgate lock is still playing up. Can only be opened manually with a key turned to extreme left, and every now and again when the key slot is in the vertical position the tailgate opens itself. So I have to maintain it in the horizontal position. Hopefully it is just a small component change in the tailgate. Anyone else had this problem and if so, what did you do to fix it??

 

I have an 04 A4 Avant and the rear latch will not respond to either the fob or the key-in-door sequence. Will lock, but will not unlock.
I assume I need to replace the unit in the hatch, but any advice will be appreciated.
RLG