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- Audi A6 C6 and A6 C5 Trunk Latch and Mechanism<br>Guide to diagnose trouble and recommended solutions.
Trunk latch won't lock!!!
12-29-2010, 12:58 PM
#11
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So I just fixed mine completely.
1. The lock cover just pops right off.
2. The inner lining has eight small steel popping fasteners around the edges, these just pop off. In addition you need to remove two screws, one located under the emergency trunk release handle (you can pop the handle right off to get to it) and one on the right side inner trunk lid closing handle.
3. Once you get all of the screws and fasteners off, you need to pop the emergency handle assembly off the liner, pop it out toward you, and then put it back through the hole in the liner so that it stays attached to the trunk.
4. After you have removed the liner, remove both nuts holding the lock to the trunk lid. Once you get the lock off you will have an easier time getting the two mechanical cables disconnected (one from the emergency handle, and the other from the key hole). Remove both mechanical connections and the electronics.
5. I have found that the problem is not the actual latch system (metal part) but rather the gearing system within the plastic enclosure. once you open it, you will find a large gear connected to an electric motor, the gear/motor moves a plunger/screw forward releasing a latch, the plunger then travels back via spring power after it clears a small barrier (kinda like a clicking pen).
As the Lock system wears and lubricant deteriorates the plunger seems to have a hard time sliding past the small barrier, fixing it simply involves spraying the gear assembly down with some lithium lube (wd40 or chain oil would prob work too, I like Lithium because of the cold weather and consistency).
Notes: I would say to just use a little tube to spray within the assembly, but because of the electronic switch and sensor within the lock, they have designed it so that you can’t get to the gear without opening the whole assembly.
There are a few springs holding parts together, use caution when opening the lock assembly, and/or take photos before you disassemble so that you can remember where everything goes.
In any case, the whole system now works perfectly again.
I have an 07 B7 2.0 quattro.
1. The lock cover just pops right off.
2. The inner lining has eight small steel popping fasteners around the edges, these just pop off. In addition you need to remove two screws, one located under the emergency trunk release handle (you can pop the handle right off to get to it) and one on the right side inner trunk lid closing handle.
3. Once you get all of the screws and fasteners off, you need to pop the emergency handle assembly off the liner, pop it out toward you, and then put it back through the hole in the liner so that it stays attached to the trunk.
4. After you have removed the liner, remove both nuts holding the lock to the trunk lid. Once you get the lock off you will have an easier time getting the two mechanical cables disconnected (one from the emergency handle, and the other from the key hole). Remove both mechanical connections and the electronics.
5. I have found that the problem is not the actual latch system (metal part) but rather the gearing system within the plastic enclosure. once you open it, you will find a large gear connected to an electric motor, the gear/motor moves a plunger/screw forward releasing a latch, the plunger then travels back via spring power after it clears a small barrier (kinda like a clicking pen).
As the Lock system wears and lubricant deteriorates the plunger seems to have a hard time sliding past the small barrier, fixing it simply involves spraying the gear assembly down with some lithium lube (wd40 or chain oil would prob work too, I like Lithium because of the cold weather and consistency).
Notes: I would say to just use a little tube to spray within the assembly, but because of the electronic switch and sensor within the lock, they have designed it so that you can’t get to the gear without opening the whole assembly.
There are a few springs holding parts together, use caution when opening the lock assembly, and/or take photos before you disassemble so that you can remember where everything goes.
In any case, the whole system now works perfectly again.
I have an 07 B7 2.0 quattro.
12-29-2010, 04:25 PM
#12
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^^^ I guarantee with you the problem will come back. The latch is sold at dealer for $47 (at least at my dealer) and it's totally not worth the time taking the trunk liner apart doing all that the 2nd time.
Last edited by BlueSander; 01-03-2011 at 10:15 AM.
01-03-2011, 02:16 AM
#15
AudiWorld Super User
Speaking from experience WD40 works for about 8 weeks and then you are back to needing to replace the latch. It is easier to just bite the bullet and replace the latch.
01-03-2011, 02:03 PM
#16
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Yes, it is a common problem. I just had this problem. The thing is that because if trunk is not closed, the alarm doesn't turn on when locking the car. You can only lock the car, without the alarm turned on. While the problem would dissapear at higher temperatures this means you shouldn't open the trunk at low temperatures. Anyway, I had to change the mechanish, it cost me 50€ in Europe + 25€ half an hour of work. At the service they told me that mechanisms for cars made in 2005 had etka code 4F5827505D, then Audi discovered the problem and they changed the mechanism so now it has the letter E or F in the code. The new one shouldn't have this problem anymore they said.
thanks
01-03-2011, 07:38 PM
#17
AudiWorld Member
01-04-2011, 05:38 AM
#18
AudiWorld Member
I once sprayed the latch with WD40 and it worked 90% of the time for a while and then back to square 1. Replaced the latch about 7 weeks ago and problem is gone. My advise to any one with this problem is to replace the latch it is cheap and easy to do.
02-19-2011, 12:46 PM
#19
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Link to walk through
I replaced mine today - thought about trying to lube it up and repair and then decided by the time I got in there to it I would be happier with a new part. The revised part is now 4F5-827-505-D. It can be ordered online for about $50-55 delivered but I wanted it done since it was a Saturday and didn't feel like waiting for it. My stealership in downtown Houston retails the part for $76.24 list but I got him to take it down to $64 which is still too high but worth the convenience.
The following post is a walk through with pictures. While not exactly the same as my A6 it would have been helpful beforehand. I ended up snapping the screw housing by the emergency release lever (not a big deal) but I would easily have avoided that if I read through this post. Hopefully this link is helpful-
http://www.audizine.com/forum/showth...ty-Trunk-Latch
Any way you look at it this is a common problem but only when cold. That is obviously not frequent in Houston but when it is cold this is a serious annoyance - well worth the 30 minutes or less to replace.
The following post is a walk through with pictures. While not exactly the same as my A6 it would have been helpful beforehand. I ended up snapping the screw housing by the emergency release lever (not a big deal) but I would easily have avoided that if I read through this post. Hopefully this link is helpful-
http://www.audizine.com/forum/showth...ty-Trunk-Latch
Any way you look at it this is a common problem but only when cold. That is obviously not frequent in Houston but when it is cold this is a serious annoyance - well worth the 30 minutes or less to replace.
02-21-2011, 06:36 PM
#20
Thanks for posting this.
I replaced mine today - thought about trying to lube it up and repair and then decided by the time I got in there to it I would be happier with a new part. The revised part is now 4F5-827-505-D. It can be ordered online for about $50-55 delivered but I wanted it done since it was a Saturday and didn't feel like waiting for it. My stealership in downtown Houston retails the part for $76.24 list but I got him to take it down to $64 which is still too high but worth the convenience.
The following post is a walk through with pictures. While not exactly the same as my A6 it would have been helpful beforehand. I ended up snapping the screw housing by the emergency release lever (not a big deal) but I would easily have avoided that if I read through this post. Hopefully this link is helpful-
http://www.audizine.com/forum/showth...ty-Trunk-Latch
Any way you look at it this is a common problem but only when cold. That is obviously not frequent in Houston but when it is cold this is a serious annoyance - well worth the 30 minutes or less to replace.
The following post is a walk through with pictures. While not exactly the same as my A6 it would have been helpful beforehand. I ended up snapping the screw housing by the emergency release lever (not a big deal) but I would easily have avoided that if I read through this post. Hopefully this link is helpful-
http://www.audizine.com/forum/showth...ty-Trunk-Latch
Any way you look at it this is a common problem but only when cold. That is obviously not frequent in Houston but when it is cold this is a serious annoyance - well worth the 30 minutes or less to replace.