Central Locking Intermittent Fault

Poor_John

Poor_John

Member
Symptoms

Remote central locking does not work and light on driver's door is on steady or off (not flashing). After unlocking door with key, alarm goes off when door is opened. Engine starts okay, but can hear a regular clicking sound as if doors are being unlocked. Rear passenger doors do not unlock and cannot be opened from inside. Front passenger door unlocks. Alarm turns off after pressing the hazard warning light switch. Sometimes hear a vibrating sound coming from passenger foot well and sometimes can feel a pulse on the rear hatch release! The door unlocking sound continues while I drive off and stops after a five minutes or so when a sound like the rear hatch unlocking is heard.

Any suggestions as to what I should look at? Probably the Central Convenience Unit me thinks. Could it be something simple like a relay? Car is in regular use, but I suspect something is draining the battery as the car is dead after standing for a couple of weeks.

John.
 
Update

Car is now off the road. I went to start the car first thing in the morning and although starting okay, the alarm would not turn off and the central locking was going mad, constantly trying to unlock. The hazard lights were flashing very very fast - like a strobe light. To stop annoying the neighbours, I disconnected the battery! I couldn't think of what else to do:D

I took the battery out and charged it for 24 hours. When I reconnected the battery again this evening, the same symptoms came back, so I disconnected the battery again and had a think and a good search of this site.

If I have read correctly, the reason why I cannot turn off the alarm is that the key needs to be re-synced. I will try this tomorrow:

Manually lock the car with key, remove the key from the lock and then re-insert it and unlock it.
Put the key in the ignition and start the engine.
Run the engine for a few seconds (10 is plenty) then turn off the engine and remove the key.
IMMEDIATELY PRESS THE UNLOCK BUTTON ON THE KEY FOB. The indicators will blink and the key is re-synced.

Thank you Skipton01 for posting the instructions.

Probably a good time to change the battery in the key fob as well.

I will keep you posted with progress. I will be good to get to the bottom of all this.
 
Sorted! I think...

Put a new battery in the key fob and set to on the car before it got dark. Reconnected the battery, alarm went off etc, went through the key re-sync process. Alarm stopped. Progress! Started the engine again, the central locking was still trying to unlock the doors every second, the key fob neither locked nor unlocked the car, the rear doors were still refusing to unlock, the driver's door inside lock switch was lifeless and there was a vibration coming from the passenger foot well. Lifted the carpet, removed the lid and found the sound to be coming from the large black box - central convenience unit? Is there a relay inside it? Took the car for a spin, but the vibration from the foot well continued. Parked the car up, locked the door with the key in the door and went in to have tea.

Came out about an hour later and the remote worked! Engine started! No noises from passenger footwell. Happy days! Took it for a drive. No problems.

The big test will be on Monday morning. It would be great if all it turned out to be was a nearly drained battery.

John.
 
Think my battery is starting to wane (52). When starting in the morn it is taking a little longer and the displays are dimming more.

Skipton (or anyone else), I'm not sure of the radio code but when you fitted the cruise there was not a problem when you disconnected the battery. Will it be fine just to switch for a new one?

Cheers

Neil
 
badlyread said:
Skipton (or anyone else), I'm not sure of the radio code but when you fitted the cruise there was not a problem when you disconnected the battery. Will it be fine just to switch for a new one?

Cheers

Neil
Click to expand...

As long as you do the swap in under an hour, and you don't physically remove the radio from the cars' wiring loom (no reason to, I know), then there will be no need for the security code.

Cheers,

Mike
 
Didn't have a long wait

Well I didn't have to wait for Monday morning. The light on the driver's door was lit up first thing this morning. Unlocked the car with the key in door as the remote would not respond. Alarm did not start when I opened the door, but started when I put the key in the ignition. Started up engine and after a while the alarm stopped. I have been driving the car on and off all day and everything returns to normal after driving for a while. The only thing not normal is the vibrating coming from the CCU, which has become intermittent.

From what I have read here, a faulty / sticking micro switch in a lock could be causing faults. My next thing to try is to spray WD40 into the locks. Can anyone identify where I should spray in the front service flap as I believe this, like the door locks, has a micro switch?

I see Mr Angry has a CCU up for sale. How can I be sure the one he is selling is right for my car and is it a simple plug-in job?

John.
 
badlyread said:
Think my battery is starting to wane (52). When starting in the morn it is taking a little longer and the displays are dimming more.

Skipton (or anyone else), I'm not sure of the radio code but when you fitted the cruise there was not a problem when you disconnected the battery. Will it be fine just to switch for a new one?

Cheers

Neil
Click to expand...

Hi Neil,

Page 30 of the Audi Concert Sound System Operating Instructions has the following information that you may find useful:

Convenience Radio Coding

For technical reasons, the convenience radio coding feature is not available for all models.
With the normal type of security coding, the radio had to be re-coded manually every time the battery was disconnected or the unit was removed from the car.
The new convenience coding is much simpler: once the radio has been coded, it will syncronise itself with the vehicle it belongs to.
If the battery power is then interrupted at any time, the radio will automatically check to see if it is still in the "right" vehicle when the ignition is switched on. If it recognises its own vehicle again, the radio will be ready for use after a few seconds.
This means the radio no longer has to be re-coded manually after it has been disabled by the anti-theft device.
However, if the radio has been fitted to another vehicle, it will have to be reactivated by entering the correct code.

I have had the battery disconnected for over 24 hours and the radio has not needed re-coding. My car has a Concert 2 fitted.

John.
 
try another drivers window motor which comes with the convenience unit attached. i think there are some sort of dodgy micro switches in there that go after a while. replaced mine and the mullarkey stopped
 
Hi d4v1d sm4rt,

My car will be making a visit to the dealers to have it plugged into their diagnostic computer near end of this month. I asked around who could diagnose my car and was told it was a job for Audi. It seems they are the only people who have the appropriate equipment around here.

The problem seems to be temperature related, as on mild mornings everything is normal.

John.
 
how much is the diagnostic palarver going to cost vs £50 for a second hand regulator with electronic box attached. Even when they do "diagnose it" you will still have to replace something (most likely that unit) so you will have payed twice and you will no doubt pay for the unit at full retail. Its worth a £50 punt in my book. i did and it worked.
 
Komfortelektronik

Hi All,

Just picked car up from dealer. They replaced the komfortelektronik control unit, part number A8Z0 959 433 Q and the battery in the key fob. Key was coded to new unit. Everything seems fine, but tomorrow morning will be the test. Car was washed, vacuumed and tyre walls blackened. They even recorded the tyre tread depths on the receipt. £427.25

Three lovely new R8s sitting outside the showroom. Did someone mention recession???

John.
 
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