A6 2003 central locking problem - HELP!
 

Hi, I have browsed the forum and google for solutions but could not find anything directly relevant to the problems I experience. I am hoping someone here will be able to help? I am giving a precise description below, which I hope will encourage the fellow forum members to a valuable response...

THE CAR:
A6 (C5) 2003 avant sport 1.9 TDI - UK version (right hand drive)

BACKGROUND:
The car was left for 10 days undriven while I was away for xmas. When picking it up from the airport I could not open via key fob and opening drivers door with the key does not open other doors. Passenger door and rear doors cannot be opened from the inside either and alarm goes off as soon as the driver's door are opened by inserting the key.

THE PROBLEM:
a) I investigated a bit more upon my return from the airport. Initially I thought the fob battery went flat so I tried the spare key which has worked in the past - but with no effect.

b) When turning the key to the right in driver's door only that door opens (button goes up). after physically opening the door the alarm goes off and can be only disarmed by turning the key in the ignition.

c) All other doors can't be opened from the inside: when pulling the inside handle the button goed up but as soon as the handle is relased the button goes back down (pulling the outside handle when the button is momentarily up does not one the door either).

d) I can't disarm the alarm by pressing the button near driver's door (the LED does not switch on when the button is pressed).

e) The central locking 'lock'/'unlock' button on the driver's door does not function. When pressing the 'lock' I can hear the door solenoids closing the already locked doors but the 'unlock' does not provide any audible feedback.

f) Other observations: the battery voiltage is correct 12V with ignition off and 14V with alternator running. When opening/closing the door by turning the key in the driver's door the indicators do not flash as they would if the central locking was operational.

g) I have been reading the central locking threads on various forums and found out that the central locking unit often is subject to excess moisture and connector contacts tend to oxidise which can casue malfunction of the system.

QUESTIONS:
1. has anyone came across the particular problem when ALL passenger doors stay locked even when the key in the driver's door is turned (that indicates a general fault of the centra locking unit, not a fault of a single lock). Did you manage to fix it yourself? If not what's the cost of fixing by a garage?

2. WHERE is the central locking unit located (UK right hand drive)? How do I get to it? (any instructions would be helpful). I am an electronics engineer and I suppose I can investigate the problem and attempt a repair before taking it to the service.

3. If I find that the central locking module is irreparable, what is your experience with replacing the module? Does it need to be re-coded, can it be done by myself or only by the service?

4. Can I learn something about this problem from OBD-2 connection by hooking up the VAG-COM cable? I have a cable and software I used in the past on my previous A4 but I do not know where is the OBD-2 socket located in the A6?

Should be able to learn by hooking up the OBDII socket. On North American cars it's on the left hand side of the center console. Look under the knee bolster (but you don't have to remove the knee bolster).

OK I will try that first thing tomorrow when I get some day light :)

You'll need to get into the measuring blocks for the convenience group and start verifying that the switches are working. Start by checking the switch in the driver's door latch.

First of all the fault codes:

01557 - Contact Switch in Locking Cyl: Driver Side: Open (F241)
29-10 - Short to Ground - Intermittent
01374 - Alarm triggered by Terminal 15
35-00 - -
01370 - Alarm triggered by Interior Monitoring
35-00 - -
01559 - Drivers Door;
58-00 - Can't lock


4Driver4 thanks for the tip - I am not experienced vag com user. I did as you suggested and can conform that all seems to be correct. Here is what I have done:

After connecting the VAG-COM cable and clearing the fault codes the driver’s door ‘lock’/’unlock’ button now unlocks all the doors (the keyfob still does not lock or unlock the doors)
As soon as I lock the car by turning the key in the driver’s door – all doors lock and do not unlock when the driver’s door is unlocked with the key turn. The situation is back to the starting point! And the driver’s door switch does not unlock the door anymore too!
OK so cleared the fault codes again and get the driver’s door switch to unlock all doors.

Measuring blocks / basic settings:

1. door unlocked - see attached screenshot 1
2. door locked - see attached screenshot 2
Pulling the individual door handles / pressing the door buttons down now changes the status of each door to unlocked / locked as expected

3. With the key in ignition I used another key to lock the car by turning it in the driver’s door. That locks all the door. When turning the key to unlock the driver’s door - this changes the status of drivers door to unlocked - see attached screenshot 3. But turning the key in driver’s door would normally unlock ALL doors! And it doesn’t... Shortly after turning the key the Status of Group 001 changes to 'Open' to go back to 'Not Open'. After 2-3 seconds. I interpret it as an attempt to open all doors (?) but what stops the other doors from actually unlocking?
After using a key inserted in the driver's door lock - the driver door’s ‘unlock’ button does not open the door anymore. so back to square 1.

I can make the most sense out of 01557 - Contact Switch in Locking Cyl: Driver Side: Open (F241)
29-10 - Short to Ground - Intermittent

Any ideas how to get to that switch and where is it located in the driver's door? I would like to check it out. Any tricks when removing the door card? It will be the time for me so I could use some of the experience you might have. Thanks in advance for all your replies!

missing attachments
 

oops forgot to attach the screenshots to the previous post. Here we go...

Interesting. I'd probably take the door panel off or check the wire loom at the hinge. The short to ground code sounds like a chafed wire to the lock cylinder.

Hi was this problem solved, I have the exact same problem! Please help

The lock module in the DS door can short out & cause unplanned behavior of the automatic door locks & windows. We're still on the temporay fix of unplugging the lock module.
http://www.audiforums.com/forum/members/cruby-133857/

Hi there, Just to let you and anyone else with these symptoms know:

The problem with mine was the driver door lock is in someway faulty, my key went out of sync when it opened in my pocket and because of the faulty door lock I could not do the sync thats described in my manual, I had the key resynced with a proper diagnostic, I think its VCDS.

Thanks Again