Central locking not working

J

Johnnyuno

Member
Good evening
Got a bit of a strange one hopefully someone might be able to help me out with some advice?
Bought a y reg 2001 tdi se and the central locking unlock or lock doesn't work from the keyfob thought it would probably be the battery in it but no joy.
But the unlock doesn't work from the door lock either it only unlocks the drivers door only and then when you put the key in the ignition and turn it on the rest of the doors unlock.
But when you lock the car from the door lock all doors lock very strange?
The unlock/lock button works and all doors lock and unlock as they should.
The closure of windows when they are down key in the door hold to lock position works and doors lock windows go up but the windows down function doesn't work and only opens drivers door.
On vcds comes up with excessive comms errors on the central conv and won't connect to it?
Does this mean the ccu has had it?
What's involved in changing this?
Sorry for the long winded post but wanted to put as much info as I can.
Thanks
Johnny
 

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First thing to do is check the CAR battery. Could well be too old and past it. Try recharging the battery preferably off the car. Be aware that when you shut the tailgate with no battery connected you will have to use the emergency release located in the trim around the rear window. Pain to reach so best to fold down the rear seat and remove the false floor and retractable parcel shelf to give easier access to the battery location. Refit the battery and rescan.
 
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The first thing to try is to put one of the keys in the ignition and turn it on (not started). With the ignition on press the lock and unlock of the key that is in the ignition and then remove it from the ignition straight away and then try it out.
If it works, do it with the other one.
It is a longshot but that should work if the keys have ever been paired to that car before.
Steve B
 
There is a setting in VCDS that changes the locking to just unlock the drivers door so that might explain that issue.

if you unlock twice it may open the other doors.

Steve B
 
Battery I'm the car is all good and I have tried all the shenanigans of trying to get the fob to sync with the car but the fact still remains it should work off the door lock even if the fob has a dead battery I believe?
 
Birchall said:
There is a setting in VCDS that changes the locking to just unlock the drivers door so that might explain that issue.
Is that not just for the first touch of the button but the lights should still flash and the sound of the door lock where as it's just the manual turning of the key turning which is opening the lock.

if you unlock twice it may open the other doors.

Steve B
Click to expand...
 
The unlocking bit is just the mechanical turning of the key, I understand that if you turn it twice the rest of the doors should unlock and if you hold it in that position all the windows should roll down but it doesn't. It's like unlocking a car with a dead battery.
The keyfob is completely unresponsive but it should still work off the key in the door.
The bit I don't understand is it works to lock all the doors and the closure works very strange??
 
It does sound like the CCCU may be having issues. Are there any other symptoms? Alarm, interior lights problems.

another longshot isto disconnect the car battery for 20 minutes and try again. That does occasionally help by resetting the cccu.

worth a try?

Steve B
 
I'll give that a go but I reckon as vcds won't talk to the ccu I think it's probably faulty.

What's involved in changing the ccu??
 
Pretty much plug and play.
If yours has a part number ending in Q then they are the least reliable.

if you can change it to one ending in AF then that is better but it uses a different frequency so your current remote halves won’t work with it so try to get the remote halves with it.
Unplug the old one, plug in the replacement then code the remotes with VCDS and away you go (if you get a replacement with the same part number.
Steve B
 
So if I have one with the remote halves can just plug in and it will work?
As I have access to another 2001 a2 tdi with remapped ecu.
Can I just swap the ecu and the ccu with remote and it will work??
 
Hi folks,

I suspect that there are two simultaneous faults at work here. One is a faulty CCCU and the other is a failed solder joint in the driver's door lock circuitry. There are 5 microswitches inside the driver's door lock, so plenty of circuits to go wrong, creating somewhat bizarre behaviour.

The CCCU comes in two generations, with the later generation being the much more reliable. You have the earlier generation. If you buy a replacement first-generation CCCU, you can keep you existing key fobs. If you choose to upgrade to the later generation, you'll need to replace the key fobs. In all cases, the keys will need to be matched to the CCCU, and the replacement CCCU will need to be correctly matched to your car.
Earlier this week, @Darpod14 visited me to fix various electrical problems with his car. Among them was a central locking fault; the car wouldn't register the rear doors as having opened, creating the possibility of the car locking itself with the keys inside. Normally, this behaviour would be attributed to door microswitches, but it was being caused by a CCCU that hadn't been correctly matched to its host car. It is a myth that the CCCUs are plug and play.

Cheers,

Tom
 
I 2nd this ? don’t mess around with CCCUs, just get it checked properly, if your not great at electrics, visit an expert @timmus, for little real cost you can have your little aluminium wonder doing what it should!
 
Swapping a CCCU to just determine if the original one is faulty is worth a try. Please don’t even think about swapping an ECU!!!! You don’t have to swap the ECU when swapping a CCCU.

But do please take head of Tom’s warning about the doors. But if it is not a permanent swap it might just help to determine if the CCU swap fixes at least some of the errors. You may even be lucky and it might work ok. But the micro switch in the door lock might be a secondary issue to watch out for.

The remote halves should work and if they don’t you can pair them again using the process I mentioned, failing that you might need to use VCDS to pair the remotes. (If you want to make it a permanent swap.)
I have done that many times and it has worked every time.

Steve B
 
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By the way I am not contradicting Tom’s advice. He is the Guru. ??
All I am saying is that I have swapped at least 20 CCCU’s without causing any issues.
But I checked that all doors locked and unlocked after the swap. Any that didn’t were due to (in my case) faulty door micro switches.

Steve B
 
Birchall said:
All I am saying is that I have swapped at least 20 CCCU’s without causing any issues. I checked that all doors locked and unlocked after the swap.
Click to expand...
All UK A2s, irrespective of spec', have remote central locking. A majority of UK A2s were sold with climate control, and without rear electric windows. Consequently, there is a chance that a CCCU sourced from car A will be compatible with car B without having to make any coding changes. But nevertheless, it's being left to chance. Whoever fitted the replacement CCCU to @Darpod14's A2 either believed the 'plug-n-play myth' or didn't have the necessary knowledge and/or equipment to do the job properly.
Just because the doors lock and unlock properly doesn't mean everything is hunky-dory. @Darpod14's doors were all locking and unlocking just fine, but the CCCU wasn't registering their open/closed status due to incorrect coding. As another example, the owner of a car with heated mirrors fitted could find that the heated mirrors no longer work after a CCCU swap unless the replacement CCCU is correctly matched to the car.
The coding of CCCUs in the UK is drastically different to those in Ireland, despite both vehicles being right-hand-drive. 15 years after production ceased, many A2s have crossed the Irish Sea in both directions. There are a couple of Irish A2s in my area (I live on the west coast of England, near ferry ports) and there are plenty of A2OC members in Ireland who have imported UK-spec A2s. All manner of issues would arise in both specifications of car if a replacement CCCU were to be fitted without properly matching it to its new host car.
I could be in danger of labouring a point here, but we must get away from this idea that CCCUs are plug-n-play.

Darpod14 said:
if your not great at electrics, visit an expert @timmus, for little real cost you can have your little aluminium wonder doing what it should!
Click to expand...
If a CCCU replacement is needed, there's isn't even the need to visit me. The whole process can be done remotely. Please see this thread...

Service Offered: CCCU Replacement

Hello fellow A2OC members, As part of my ever-expanding list of A2 services, I offer a CCCU replacement service. Earlier A2s in particular suffer from an unreliable Central Convenience Control Unit (CCCU). A faulty CCCU can cause a variety of bizarre symptoms affecting the interior lights...
www.a2oc.net

Kind regards to all,

Tom
 
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Interesting thread on coding CCCU's on this very forum Here

Almost no traffic on the thread so not sure how many people have tried diddling around in this area, although now I've seen it I don't suppose I'll be able to resist getting in there.

I quite fancy the option to turn on the coffee-maker after driving 75 miles for instance (although I might have dreamed about that one).
 
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