Ridge's electric/CCCU problems

Ridge

Ridge

New Member
Finland
Hi, a new person here.

I just bought a 2001 A2 1.4 gasoline. It has a few electronical gremlins. I have read your threads about the Central Convenience Unit (CCU), however, I'm unsure whether my problem is due to that. My remote key works sometimes (hence I don't think it's a sync/pairing issue), but most often not. I have to keep pressing the open button for 5-10 times and it can suddenly open the doors. Same with closing. There don't seem to be any central locking or window issues using non-remote ways.

Buying a new CCU and having to code the remote keys again is somewhat expensive so I'd rather have an opinion whether the cause here really is the CCU?

The other electronical problems I have is that the indicator keeps making noise even when the indicator's not on. However, the indicator functions properly otherwise. I'm replacing the indicator relay. I also have issues with a Sony radio installed by the previous owner that's just frozen. And also a wiring issue which lights the airbag light. I don't think all these four issues could be connected?
 
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Hi

Are you able to get the car scanned. It will be a useful starting point to understand if any errors are being recorded. If you are OK with PCs you can download a copy of VCDS Lite and scan yourself. Also how’s the battery. Low voltage can cause some errors

J
 
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birtyA2 said:
Hi

Are you able to get the car scanned. It will be a useful starting point to understand if any errors are being recorded. If you are OK with PCs you can download a copy of VCDS Lite and scan yourself. Also how’s the battery. Low voltage can cause some errors

J
Click to expand...
I'm not able to get a scan right now, but yeah maybe I should obtain the tool myself... The last owner only gave me one diagnostics error code, for the airbag, which was 024C Driver side front airbag igniter circuit 1 Highly resistive. He said that should be one wire behind the wheel. I'm having some trouble with that because apparently Airbag Wiring Harness 8Z0971589M has been discontinued, but that's probably something a VAG specialist repair shop 200 meters away from my home can fix. However, I fear that they don't work on a lot of A2s, so something like CCCU issues are something I would try to fix myself. I will 100 % take the car to a repair shop at one point though for the brakes atleast.

I've owned the car for 4 days now and yesterday the battery died. Maybe it was me trying to fix the radio without having the engine on, or then CCCU is draining my battery. I found a very interesting thread here which says their CCCU caused battery drain. Also the thread author says the remote key worked only occasionally, which is exactly my problem. I already emailed "Lau" who fixes CCCUs in Germany asking if he's still doing it, but no reply so far. My CCCU is 8Z0 959 433 C.

I guess the seller wasn't too open about the extent of the electrical issues, but I can't blame him because I paid next to nothing for this. Apparently this A2 is an original Finnish car and not a used German import like many.

I'm assuming I have to change the CCCU at any rate. But I would appreciate if someone could clarify this, which I felt like had conflicting information in previous threads:
  • a) If I repair my 8Z0 959 433 C, I don't have to program anything, just re-sync my keys by pressing open when they're inside the ignition?
  • b) If I buy a single index CCCU (maybe N or M are more reliable), my old remote keys have the right frequency but I have to program them with VCDS?
  • c) If I buy a double index CCCU (like AF), I have to purchase new "D" index keys and they have to be programmed? Also since I have manual rear windows, channel 61 needs to be re-programmed? And it's still possible that rear doors will have central locking issues or was @Tim147 just unlucky!?
 
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Hi

There may be be chicken and egg situation going on here. Are you getting CCU related problems due to the battery or is the CCU faulty and causing a drain on the battery?

It might be worth reaching out to @timmus on this one for the options open you and indeed he offers a service to A2OC

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

At a glance I believe you have got it right with a), b) and c), generally I understand AFs are considered more reliable than the earlier versions such as the one you have but I don’t know why. From some of the threads I have read you may encounter dry solder joints if you decide to have a go at repairing the CCU.

I would recommend ruling out battery problems, do you know how old it is?

J
 
Hi, you do not say if you have just one remote key or two. If two, then are they both unreliable? Try to rule out the keyfob battery (CR2032), a weak battery can cause intermittent operation. Also a bad 12V car battery can cause a bunch of issues including central locking issues. It sounds like your 12V battery is weak or not charged properly, just playing with the radio should not drain it completely. The CCU is not the only thing that can be faulty, other parts of the system are just as likely (electronics/electrics inside the doors). Listen out for 'double-cycling' when locking/unlocking, this is caused by lock open/closed states not being detected correctly - the CCU then attempts to repeat locking/unlocking operation. Usually this is caused by dry solder joints in the door lock PCBs - in my case all 4 doors had this problem. There have been reports of worn microswitches also resulting in the same symptoms. One possible failure mode is that the apparent state of a microswitch is constantly or intermittently changing between open and closed, the electronics in the door continuously reports this to the CCU and drains the battery in the process. I would expect this to cause other symptoms - perhaps alarm going off for no reason, maybe intermittent keyfob operation as you describe. I had a faulty door control unit that was causing all kinds of mad things to happen (affected alarm, central locking, electric windows, interior light, fuel flap) probably because it was 'flooding' the CAN bus with garbage. Disconnecting that one door control unit instantly made everything work normally again (apart from the affected door obviously).

I would definitely rule out bad 12V battery first, as this is very common. If you can get hold of a DC current clamp meter, I would suggest checking the current drain at the battery terminal with the car locked, this should be <<100mA within a few seconds of locking. If you find that the current drain is much higher than this, then you can try to eliminate each door in turn by disconnecting the door control units one by one.
 
Thanks, both of you! I can confirm that I have two remote keys and they both have the same issue. I just tried and had to keep pressing the open button 10 times until it finally opened. However, when it did open, all doors were correctly opened.

I also experienced something new: on two occasions hitting the remote key, the car didn't flash turn signals or actually open the doors, but the interior lights were turned on!

The battery doesn't have a date, but it doesn't look older than a few years at maximum. I recharged it with a digital battery charger (it said it was full c. 6 hours with 6A). And the radio and remote central lock issues were still there even when the battery was fresh. My wife went to work with the A2 today and the battery's not dead yet. Unfortunately I don't have a clamp meter.

I'll probably message Timmus if he still services CCCUs and could send a post package (and hope that the microswitches and door control units are fine). My second option is to buy AF-index CCCU from ebay. But it's probably not a bad idea to change the CCCU given that it's 2001 C model in any case.
 
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The buttons on the remotes could be worn and the batteries nearly flat in the remotes. Start with 2 fresh batteries in the remotes and see if things improve. After the battery change you will need to resync the remotes to the car.

Also do the keys work better if standing directly behind the right end of the rear bumper?
 
Have you inspected the CCU compartment in the passenger footwell? It is common for these to get moisture inside them, I have seen photos with extensive damage. I found water in mine after driving through a puddle at speed. Check battery voltage with a voltmeter, should be 12.4V or higher after an hour or more of inactivity.
 
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audifan said:
Also do the keys work better if standing directly behind the right end of the rear bumper?
Click to expand...
No.
ukrainian said:
Have you inspected the CCU compartment in the passenger footwell? It is common for these to get moisture inside them, I have seen photos with extensive damage. I found water in mine after driving through a puddle at speed. Check battery voltage with a voltmeter, should be 12.4V or higher after an hour or more of inactivity.
Click to expand...
Yes, I opened it to check my model #. It didn't look damaged or damp from the outside, the box that is.


I bought a current meter and my battery was 12.55 V two hours after driving (and two days after full recharge).

To measure battery drain, I locked the doors, waited a couple of mins and took the minus cable off the battery. Then set the meter to 10 A and put the red cable on the disconnected minus car cable and the black cable to the battery terminal.

0.31 drain from the battery!
I took fuse 36 (interior lighting, heater, air conditioning) off and got 0.22.
Then I took fuse 42 (central locking, int. lighting) off and it was 0.15.
Finally, I took door control unit fuses (39 & 41) off and the result was 0.

So CCCU seems to be the fault here, those are all related to it? Unless there's also a faulty door control unit. The wires between the doors are protected by a rubber cover which are not damaged at all.

I put the fuses back in and now my central locking doesn't work at all. Could I have somehow damaged the fuses? (EDIT: Started working, after I opened them from the driver door button once). Also bizarrely, I paid 20 € for a fault code check but it gave EOBD error two times and couldn't read the codes. I got my money back, and the operator said it's possible that there's a fault in their equipment too, but that didn't help.
 
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Not sure what the exact ampere (sub?)unit would be, but 0.31 was indeed the result without removing any fuses with the 10 A setting. Everything in the car had been locked and shut off for a couple of mins as I mentioned. Obviously the driver and trunk doors were open (but locked) so I could perform the checks.

index.jpg
 
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Ridge said:
c) If I buy a double index CCCU (like AF), I have to purchase new "D" index keys and they have to be programmed?
Click to expand...

The double index CCCUs use a digital protocol for connecting to the remote fobs, rather than the earlier analogue protocol. They are way more reliable than any of the early CCCUs, to the point where repairing an early CCCU is simply a waste of time.

You don't need new keys to go with the CCCU upgrade, but you do need the matching remote fobs.

If you have a registered copy of VCDS-Lite, you can use that to pair the new fobs to the CCCU.

The simplest solution is to ask @timmus to supply a later CCCU with two matched fobs. He will sort out all the initial programming ahead of despatch, and give you very clear instructions on how to get everything installed and set up. Rest assured that he won't leave you in the lurch!
 
It looks like your battery is ok. The current draw seems a little high but assuming an 80Ah battery it would still be ~10 days before it is fully drained. It is possible (likely) that the current draw is higher because the door is not actually closed - the CCU should be 'aware' of this if the microswitches work as intended. I was able to do these checks with the boot lid open because the microswitch in my boot lock is stuck 'closed' so my CCU 'thinks' the boot is shut always. You should be able to lock the car from inside (disable the interior motion detector first). If you suspect a door control unit you could eliminate them one by one by disconnecting each one in turn.
 
Maybe an admin can split this thread from my first post to a new thread like "Ridge's electric / CCCU problem"? Wasn't a good idea to hijack an old thread with this extensive issues. Sorry!


I got a fault code check from a self-service station.

System: Immobilizer, Immobilizer/instrument panel Diagnosis​
*01330 Control unit for comfort functions​
*01333 Left rear door module​
*01334 Right rear door module​
​
System: Restraints, Airbag Airbag 5​
00588 Circuit Airbag driver​
*01217 Side airbag deployment circuit, driver's side​
​
System: Air conditioning, Air conditioning Climatronic​
00818 Evaporator temperature sensor​
*01330 Control unit for comfort functions​
*01206 Time signal ignition off​
​
System: Instrument panel, Device Diagnosis​
*01330 Control unit for comfort functions​
*01333 Left rear door module​
*01334 Right rear door module​
​
System: Multifunction, Comfort system Diagnosis​
*01330 Control unit for comfort functions​
*01561 Left rear door​
*01561 Left rear door​
*01561 Left rear door​
*00955 Key 1; adaptation limit exceeded​
*00956 Key 2; adaptation limit exceeded​
*01331 Driver's door module​
*01332 Passenger door module​

I don't know how old those codes are, they were all reset now and just two of them instantly reappeared on ignition (Circuit Airbag driver & Evaporator temperature sensor), but for sure many more will reappear.

Not sure what to make of it exactly. I'm surprised all the door modules give a fault code because they work as the central locking works via the key blade. But there's also a code for the CCCU, maybe it causes fault codes for all? Also key adaptation limit is surprising because remote opening occasionally works and I've tried the key-in-ignition-press-remote-open resync method.

Bought a new radio which is working. But even if I lock the doors, the radio will stay on unless I manually shut it. Sigh.
 
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Ridge said:
Not sure what the exact ampere (sub?)unit would be, but 0.31 was indeed the result without removing any fuses with the 10 A setting. Everything in the car had been locked and shut off for a couple of mins as I mentioned. Obviously the driver and trunk doors were open (but locked) so I could perform the checks.

View attachment 102738
Click to expand...
0.31 Amps = 300 milli amps. Milli Amp (mA) = 1amp/1000. So 310 mA.
Mac.
 
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Regarding the fault codes - the numbers can be decoded into more meaningful descriptions, if you have access to the manufacturer's documentation. VCDS-Lite codes can be looked up online at ross-tech.com and often suggest possible causes for the fault. Without this additional information it is difficult to judge what is the primary cause, it could be the CCU and it could easily be the door modules as well. As you say some of these codes can be intermittent, some probably caused by your experimentation when taking fuses out. Dry solder joints can easily result in intermittent faults, perhaps infrequent faults. I did not even realise there was a problem with mine at first because the doors locked and unlocked ok, but the locks were double-cycling - listen out for that, it may not happen every time. Hopefully Timmus has a good idea what to do.

If you're interested in being able to read the fault codes yourself, I found it was easy to do with a cheap adapter (I bought a blue KKL VAG-COM 409.1 OBD2/OBD scanner for < £10). It uses the CH341 chip from WCH (cheap alternative to FTDI chipset) but works just fine. You will have to download the USB driver for it from the internet, as well as VCDS-Lite.
 
A couple of updates if it helps someone else diagnose problems.

I had the pretty rare airbag fault code (024C Driver side front airbag igniter circuit 1 Highly resistive) and a MOT test this week so I had to bring it to a repair shop. This garage was a pretty scruffy looking, but the mechanic apparently had worked over 10 years for the Volkswagen importer. He went through all the wiring which were OK, and concluded that the clockspring needs to be replaced. He called me to inform that the OEM part is 800 €, non-OEM 400 €. I picked the latter, and of course had to pay for the diagnostics work too. I later noticed that junkyards sell the clockspring part from a 2005 Passat, albeit with a different index letter, for 100 €. That annoyed me, but hey, probably parts related to airbags are better to be newly manufactured...

Car passed MOT without any notifications from the inspector. He only said that the rear drum brakes seem to have scaly rust on the exterior.

I also replaced the indicator relay because I had problems with the indicator click sound being played for no reason. Sometimes the sound went completely crazy, clicking 100 times in a row. But the problem persisted even with a new indicator relay. So I found a Youtube video which said to put contact cleaner spray and compressed air inside the indicator stalk. That really worked! Hopefully I can return the indicator relay (50 € part) to Amazon now.
 
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