[SOLVED] Audi S8 2002 - Can't unlock using key
 

Hi guys,

This issue is puzzling/concerning me. Has anyone come across this before or get any ideas what the cause may be? ...


My car is an Audi S8 2002 (Final Edition, D2).


Problem: I can lock but not unlock the car using a key, from either the driver's door or the boot/trunk.
(regardless of whether the car was locked using a key or a fob)


Things I've checked:

• Lock and unlock using the Remote key fobs works.
• Lock and unlock using the internal door switch works.

Which initially led me to think the problem must be a faulty door lock switch, but here's the strange thing ...

• When attempting to unlock the door with the key, even though the car doesn't unlock, the interior lights come on.
• And even stranger; if the ignition is switched on, using another key, the car can be locked and unlocked using a key in the driver's door.

Now I recently coded a few more key fobs, using VAG COM (which worked fine), but I've never really had the need to unlock the doors using the key, so I don't know whether it's something I've screwed up with VAG COM or whether it's always been like this. Either way, it concerns me that if there were a problem with the remote key fobs in future, I would have no way to unlock the car.


Any help/suggestions would be much appreciated :)

Interesting.

I was 99% sure that the key unlock in the drivers door, and boot for that matter are entirely mechanical. They are designed to operate with a flat battery, so, if the key fits, and turns, it should open regardless....:Confused:

Once the door is opened, you have to put the key, with the immobilser chip in the ignition within 15 seconds to disable the alarm from going off.

This is the whole design of the small black wallet key.....

Its interesting that you can lock, but not unlock. I didnt think the D2 had any sort of deadlocks, so maybe there has been some sort of physical damage to the lock ?

With power, when you turn the key in the lock, it makes contact which then activates the central locking pump, interior lights etc. If the electrical contact for 'unlock' was broken, I could see how only the drivers door would unlock and nothing else when you used the key, but I cant understand how the mechanical lifter wont lift.....

Thanks very much for the reply :)

Yeah, that's what puzzled me too.

I owned 2 A8s prior to this (a '96 and a '97 model) and I'm sure the driver's door locks operated mechanically on those. Whereas this late 2002 D2 S8 (one of the very last D2s I believe) is almost certainly not mechanically operating the lock. It 'feels' purely switch-like ... very little mechanical resistance as you turn it, other than the spring-back tension.

I was of the understanding that it does have deadlocks though. I'd have to check to confirm, but I'm pretty sure the deadlocking features are mentioned in the vehicle's owner's manual. Also, you have to double-pull on the internal handles to get out when the doors are locked .... isn't that a deadlock thing?

The boot lock feels mechanical however, but that won't unlock the car either, only the boot itself.

Well mines a 2003-reg, very late (2002 built) D2 S8 and the door key is very mechanical. Suggests something broken in yours.....

No. 1 pull unlocks it, 2nd pull opens the door. If it were deadlocks, then by definition you wouldnt be able to open it from the inside at all..... +++

From what you describe, its almost like the contact for 'unlock' is electrically not making it back to the central locking pump in the boot, which controls all this stuff.

As a wild, wild guess (As wiring is generally reliable) I wonder if anyone has ever replaced the CLP (which often fail) with slightly the wrong one, coded it incorrectly or somehow messed with the wiring plug?

Welcome by the way, always nice to see new enthusiasts who are able to articulate a well constructed post +++

I don't recall the exact pattern when I had trouble with the locking on my last 2002 S8, but it was pretty similar. I could lock on the key in the door but not unlock, and I could unlock the boot with the key, but not the rest of the car.

It turned out to be 2 faults: first, the central locking pump had an intermittent failure; and second, there was a mecahnical link in the driver's door that was disconnected.

The latter had clearly been the result of a previous owner fiddling about behind the door card and not reconnecting the link, but I'd never noticed because I'd never tried to unlock the door with the key.

BTW, an introduction and photos of your car are essential if you want the stream of advice to continue! :D

Ah, of course. Doh!

But that's the puzzling thing ...

From an electrical point of view, the central locking ECU is clearly seeing the unlock contacts close/open because, with the ignition on, it unlocks the doors (which, I must say, I find bizarre!) and, without the ignition on, moving the key to the unlock position, turns on all the interior lighting.

Why thank you kind sir .... I do try :D

I have actually posted here before ... about 4 years ago in fact, when I first purchased this car, but my user account was closed (probably due to lack of use). I've purchased countless parts from you too over the 10+ years I've owned my various '8s. Actually, I might be looking for a used, complete S8 fuel tank soon, but that's another story/thread ...

Ah, brilliant, thanks for that.

In that case, maybe mine is presently working entirely electrically and whatever mechanical linkage there should be is missing, broken or fallen off. That would make sense I think.

I was kinda assuming I'd maybe screwed something up using VAG COM, but I'm guessing it probably wasn't working before that. Time to Study ElsaWin I think, see if I can see what might be missing/broken.

Ah, great thanks. :D

That further confirms it. Gotta be a mechanical linkage I reckon.

lol

I actually don't have many photos of it, but I will take some soon and post a proper intro. I've just spent over 3K on the car in fact, getting it back to showroom condition, so I think some photos are definitely required.

Here's one from a couple of years ago: http://i.imgur.com/2o2DSQ4.jpg

Just to add that when I unlock the drivers door with the key only that door unlocks and the interior lights come on. The other doors unlock when the ignition is turned on.
When locking with the key all doors lock and the alarm chirps.

I assume that unlocking behaviour is down to the settings I have, I've changed them a fair bit (noted in another thread) with VCDS.

Ok, thanks for confirming :)

Mine doesn't unlock any of the doors, so it sounds like that part at least should be mechanical. Looks like that's the missing link(age).