Central Locking issue 2002 A6 1.9tdi

[Daubs8]

My first post so here goes if anyone can assist? Having owned every variety of VW I found myself buying an A6 from my neighbour last week as a stop gap. The central locking on the remote was dodgy to say the least as it worked intermittently and had itself trying to lock and unlock the doors whilst driving. Also had weird internal flashing lights etc. Anyhow, as a result of studying historical posts on here I concluded that it must be the known flooding problem causing damp in the comfort control unit in the foot well. I followed detailed instructions how to access the CCU and did so yesterday. It was bone dry and showed no signs of ever having been flooded. So, having been informed by the previous owner that he had replaced the guts in both doors I am leaning towards a problem with the lock isolating mechanism caused by I don't know what? The weird symptoms are as follows if anybody can assist?

The remote has completely stopped working which I can live with to sort another day.
The key opens the drivers door but none of the others.
Once inside the car the door switch attempts to open the other doors but they don't unlock.
None of the doors (apart from the drivers) will manually open from inside. They try and the button comes up slightly but retracts. This is now dangerous as the only way out is the drivers door.
If I disconnect and reconnect the battery for a moment it appears to reset the locks. I am able to lock and unlock all doors with the key in the drivers door, I can also lock and unlock all doors from the door switch however,
Having used the car if I then get out and lock it with the key all doors lock but go back to the state mentioned above meaning only the drivers door locks and it's back to disconnecting the battery to reset everything.

Before consulting an expert I thought I would give you guys a go. I can kind of live with it as I have other vehicles but I would like to sort it out and don't want to have to leave the vehicle unlocked all the time, which is the only way I can use it safely with passengers in. Thanks for your time and look forward to any suggestions.

[Peter D]

Exactly which lights are flashing. If you open each door in turn does the display show that that door is open. Regards Peter

[Daubs8]

Hi Peter. The hazard lights start flashing quickly until I insert the ignition key. I have just done the battery reset and heard on reconnecting all the doors appear to reset. Both rear doors and the passenger door show as open on the display but the drivers door doesn't? Thanks.

Chris.

[Peter D]

Either one of the micro switches in the drivers lock has failed or there is damage to the cable harness near or in the gater in the A pillar.
Beware that if this is the fault if you do not put the ignition key in the car can lock itself. Regards Peter

[Daubs8]

Many thanks Peter. I will investigate this and advise.

Chris.

[Daubs8]

Ok so I changed the drivers door lock and things have improved a little. The key still doesn't unlock all the doors but I can now lock them all with the key! Plus, once inside I can 'sometimes' open all the doors from the door switch in the panel. It will stop working but if I disconnect the battery it seems to reset it for a while. And, today I tried reprogramming the remote central locking using both keys and instructions on this site. Amazingly I can get the key to work remotely to open and lock the doors but only for 3 or 4 times then it stops again?! I think I'm narrowing it down to the CCU under the passenger seat even though I'm sure it's never been wet?

[Jeff79]

I had similar problems, changing both front door modules solved the problem, after repairing key barrel to allow fob resynch. That said, driver's door still doesn't show as open on display and key only unlocks driver door. Fob works fine after resynch, interior button also back to normal.

Could be corroded terminals on driver door lock harness connector, dodgy wires in gater (like Peter D mentioned) and/or weak battery as that can cause issues too. The water can get into the harness connector from the backside (ie; runs to bottom inside of door module, down male pins into connector).

Very interested to hear what the outcome is so I know what the problem definitely is. Like you, my CCU is bone dry with no sign of previous water ingress.

[Daubs8]

Thanks Jeff. I think I'll try the CCU unit out of curiosity and also change the passenger door lock. Still not got my head around why the central locking only works a few times after synching and then stops?! Can't think this can be down to dodgy wiring or terminals? Anyhow, let you know the outcome asap

[Daubs8]

Update: the central locking now works on the remote fob! Read somewhere that I might need to use it with the boot open as the aerial is in there and it will possibly sync the fob again. Whether that worked or I'm just lucky I don't know but it's all working. Thanks for the help.

[Daubs8]

It's fixed!!! After re-syncing the remote key again I read on here (I think) to try it with the boot lid open as the receiver was located there and it might need to 'memorise' it. Whether that fixed it or whether I just got lucky I don't know but it works.
The only other thing I did was to change the plastic runners on both windows as the windows were slow and coming down themselves (what a fix this was too)! In fixing this I had to remove the connectors to each front door lock and gave them a clean whilst they were out. So it all came together and just worked somehow?!

[Jeff79]

Good stuff :)

Sounds like there was a communication issue and you disturbed the culprit.

Gotta love cars LOL. When I was a teenager I fixed a bunch of things (usually ghetto blasters and hifis) by just taking them to bits, cleaning and disturbing stuff and putting them back together.
It's my favourite type of repair!

:D

[Tans3]

Hello, just wondering how you re-synced the remote as mine dont work

[Daubs8]

This is one method:

Press the lock or unlock button once.
with-in one minute put the key into the drivers door and lock and unlock it manualy.

if you have both keys I used this method:


open window!
switch ignition on with key you dont want to prog
manually lock drivers door using key you want to prog
wait 5 seconds then press the unlock button
wait another 5 seconds and then press unlock again and the doors should unlock.
NB This overwrites all other programming for that key.
To do another key (up to 4 max)
press unlock on both occasions twice, three or 4 times depending on number of keys.

Hope that helps!

sorry about the different font sizes I've copied and pasted!

[Tans3]

Thanks for that
Thing is I have only got one key!(sorry should have stated when i asked to question)

[Daubs8]

Try this one then if you only have one key:

Press the lock or unlock button once.
with-in one minute put the key into the drivers door and lock and unlock it manualy.

[Jeff79]

If you try the resynch procedures without success then it's worth mentioning that both the lock barrel and door module need to be in good working order for the procedure to work; if either of the two aren't functioning correctly the keyfob won't resynch. Mercifully, it's about £25 to get a module and lock repair kit off fleabay. ;)

[Jeff79]

Try this one then if you only have one key:

Press the lock or unlock button once.
with-in one minute put the key into the drivers door and lock and unlock it manualy.


This procedure worked on my 52 A6, the other procedure can be used to synch second key so long as you press twice to tell the car it's the 2nd key, otherwise you'll de-synch 1st key.

[Tans3]

No, no luck with that either, thanks

[Johnb.]

Hi guys. I have recently bought my wife a 2007 A3 Quattro. Great car, Her Subaru Legacy was a very hard act to follow. Yesterday at the local car wash, one of the guys used the key fob to open the boot. It made a loud fast clicking noise and would not open. When we got the car home, I locked and unlocked the car several times. The boot now opens and locks but the loud clicking noise is still there. Any ideas?