Problem with Battery Discharge - Suspect CCU.

Providence

Providence

A2OC Donor
Hi Everyone!

I've been a member for some time and had various problems and found lots of solutions on here. Individuals are too numerous to name but believe me, without your help my old 2001 1.4TDI would have been a very expensive car to own for the past three years!

I bought it with no useful service history. This was mainly because my wife liked the custom maroon/black leather interior! Needless to say it has needed a lot of love and attention but I think everything that previous owners had neglected has been fixed.

However it has developed an electrical fault recently in that if I don't run the car every day it will not have enough battery power to start. There is also an intermittent fault on the fuel flap release and motion sensor switches, in that they both suit themselves as to when they work!

I took it to an auto electrician this week and he told me that there is a permanent discharge of .25 amps when the car is supposed be completely shut down. He has done the pull fuses test and has confirmed that no fused device is causing this problem. He cannot take it any further, so I'm lumbered!

From my reading on this forum I am very much thinking that the CCU is stuffed.

So a couple of questions:

1. Is my suspicion of the CCU justified?

2. I have a voltmeter which will enable me to check that the excessive discharge has been fixed by disconnecting the CCU. How do I disconnect it for an overnight test?

3. If it is the CCU, how do I get in touch with LAU to arrange a replacement?

4. I have a VAG COM free version, is this capable of matching the key to the new unit?

Any help on this would be appreciated. The idea of taking it to the dealer fills me with dread!

Thanks

Steev
 
Yes, it MIGHT be the CCCU, but it might also be the alternator.

They have a "diode" or similar, that only allows the current to flow one way (from the alternator to the battery)
When an alternator breaks sometimes the diode fails too. This effectively turns the alternator into an electric motor (with a broken diode the alternator actually spins by itself if you take the belt off!!!)
I am not saying that this would be the cause but it MIGHT be.

As for the CCCU do you ever see the hazards operating when it is all locked up and left for a while?

The alarm may well be triggering overnight and since many people disable to puny little alarm horn when there is an alarm fault, you would never know!!!
Especially since you seem to think the internal sensor is faulty? What makes you think this? when the CCCU starts to pack up the alarm can trigger for no reason at all.
Do you have anyone local with a VCDS cable that can scan it for you (Edit - just s[potted your comment to say you have this), that will tell you if the alarm is being triggered and from which sensor.
It is also worth checking that your "service flap" is secure because there is an alarm trigger there too and that is often overlooked. Just check the flap is closed properly.

Disconnecting the CCCU will mean that you need to pair the keys again, but since they have already been paired to that unit you just have to place them in the ignition, switch it on and press the lock button and that will pair the key again (repeat) with any other keys, job done.

So see if you can get Halfords or similar to check the alternator (or get your electrician to disconnect the alternator and see if that resolves the drain)

So that is a couple of things to check.

Steve B
 
Last edited:
Hi as your experiencing problems with the fuel flap and alarm switch on the door pillar not working at different times. This is probably due to water or dirt getting into the drivers door micro switch. The switch will also put the interior light on --- you will notice that when it's not working the switches are deactivated and the interior light fails to come on as the ccu thinks the door is still shut. You tube has a good few videos on how to clean the switch search for mk4 golf door switch. The micro switch is not available as a part on its own so it's a new assembly.
The battery drain could be a number of things on the car but a pattern is forming that the door modules can start to draw excessive loads when idle. I'm sure a more electronically minded member will be able to guide you with a test.
Hope that helps mike
 
Thanks for the replies, so quickly as well!

Steve B

Sorry I didn't say but the auto electrician checked the alternator and confirmed OK.

There have been no alarm events and remember the electrician says there is a permanent discharge of .25 amps when the car is shutdown.

Thanks for pointing out the key matching, I hadn't thought of that!

mike

Thanks for replying. The interior light is on when the flap/motion sensor lights are off and switches are inoperable.

Can anyone tell me how to disconnect the CCU? I've seen a photo and it looks like there are loads of connections, so wanted to just disconnect the power and see if that affects the battery discharge.
 
Providence said:
Can anyone tell me how to disconnect the CCU? I've seen a photo and it looks like there are loads of connections, so wanted to just disconnect the power and see if that affects the battery discharge.
Click to expand...

Hi,

I am assuming that you know where the CCCU is?

To disconnect the power there is probably one plug that would do it, but you might as well unplug them all, it is easy enough.

Firstly remove the CCCU from its cradle (to make it easier to get to the plug release tabs)
To release the CCCU from its cradle you will just need to push in the two retainers that are on the left of the CCCU you will feel them when you d=slide your finger along the inside of the cradle at the bottom left. Push in the first one (pushing towards the front of the car) and you may well hear a click, push in the second one and the CCCU is released.

Under each connector you will feel the bit that you have to press to release the plug, you can see them if you turn the CCCU over.

Steve B
 
Last edited:
Thanks Steve.

I'm about to take the car for a spin to make sure the battery's charged and then will disconnect the CCU and leave for 24hours. I have a cigar lighter voltmeter which usually shows 11.4v after 24hrs parked, so I'll report back.

The links posted don't seem to say how to get in touch with LAU to get the replacement organised. I'd be grateful if someone could post a link to him. As I'll want to get on with the arrangements should this prove to be the fault.

Thanks

Steev
 
LAU prefers not to deal direct with owners now but A2 Cars in Milton Keynes and Timmus in Lancaster can both help with replacement CCCUs.
I suggest you send the most convenient 'agent' a PM and discuss your requirements. Both may have exchange units in stock and be able to assist with re-coding if required.

Post again on here if you need any help with this.

Cheers Spike

PS thanks for the reminder as the CCCU repair thread needs updating so we will be contacting both guys regarding the repair scheme and related services they wish to offer.
 
Providence said:
Thanks Steve.

I'm about to take the car for a spin to make sure the battery's charged and then will disconnect the CCU and leave for 24hours. I have a cigar lighter voltmeter which usually shows 11.4v after 24hrs parked, so I'll report back.

The links posted don't seem to say how to get in touch with LAU to get the replacement organised. I'd be grateful if someone could post a link to him. As I'll want to get on with the arrangements should this prove to be the fault.

Thanks

Steev
Click to expand...

around £70 or so is often the price on eBay for these, but some people try and get a lot more!!!

I bought one from Taz for £70 and just sold one through here for £50.

Quicker than waiting for a repair, as long as the replacement unit is ok.

Steve B
 
A faulty CCCU managed to flatten my battery a few months ago. A repaired unit cured my problem
 
Well, I didn't disconnect it in the end! Circumstances changed in that I need the car to be secure and running every day for a while yet so I didn't want to risk it! Strange how these things happen.

So I decided to call A2Cars and they are going to call me when there is a replacement repaired CCCU available and I'm going to Milton Keynes to get a full diagnostic done and get the offending item repaired (which Tony told me may or may not be the CCCU).

For techies reading this, there is a solid fault showing on 46 CCU when I use VCDS-Lite of:

01330 J(393) 37-00-FAULTY

Every time I reset it, it comes straight back.

I'm suddenly feeling happy that I might not be facing a big bill at the local Audi.

Thanks all for helping me out and I'll report back after the A2Cars visit.
 
Wow - so glad I jumped onto and spotted this thread.

About three years ago - during that really cold winter (-10) -my original 2001 battery became flat over night. I thought it might just be the battery or alternator needing replacing ; so I bought a new battery , and all seemed ok ,,,,, for a while

I also noticed that the alarm would sometimes randomly sound, but thought this was just the door switches (since the lights never flashed - just the annoying beep. I've learnt to live with this beeping issue - and when it happens ; I just pop outside and slam all the doors and boot).

This year - three years into the new battery - the battery was flat again , and I got really cheesed off - thinking my new battery was up the duff !

Thanks for the thread - I don't quite understand it all - but I'm a little more happy to learn that its a fault that occurs to others (not in a sadistic way ). And that at some point in the future - money permitting - I can get it fixed

Monies tight at the mo - so I think I shall just opt to unplug my battery every evening.

Cheers

Jon
 
Hi
It is worth seeing if one of our Yorkshire members could do a VCDS scan on your car to see what is triggering the alarm.

Check the front flap first though (where you have the oil filler and dipstick etc) that is the source of many alarm triggers. Make sure it is firmly closed.

Steve B
 
Last edited:
I bought one of those lead thingys for the computer, and put the software on - but it aint right good - it doesn't seem to tell me anything useful - I think I must have the cheap version (I'm Yorkshire man through and through LOL)

Thanks for the idea of giving the flap a good slap too - I'd not thought about that triggering the alarm.

Cheers
Jon
 
Well I contacted A2Cars with a view to getting a LAU repaired CCU and never heard back from them. So I bit the bullet and bought a second hand one and installed it myself and the battery discharge problem is fixed, hooray!

The only problem is that I cannot remote lock/unlock the car...

Following another thread on here I checked CCU (46) with my not fully functional free VCDS and my old CCU had:

Encoding: 06858 Shop#: WSC 00762

The new unit had:

Encoding: 06858 Shop#: WSC 02138

I edited the new unit's shop# to WSC 00762 (like my original) and it didn't restore the remote locking.

The neww= CCU is an H15 and the previous one was H14 but they are both 8Z0 959 433 Q.

Can anyone advise on what to do to restore the remote locking function?
 
Providence said:
Well I contacted A2Cars with a view to getting a LAU repaired CCU and never heard back from them. So I bit the bullet and bought a second hand one and installed it myself and the battery discharge problem is fixed, hooray!

The only problem is that I cannot remote lock/unlock the car...

Following another thread on here I checked CCU (46) with my not fully functional free VCDS and my old CCU had:

Encoding: 06858 Shop#: WSC 00762

The new unit had:

Encoding: 06858 Shop#: WSC 02138

I edited the new unit's shop# to WSC 00762 (like my original) and it didn't restore the remote locking.

The neww= CCU is an H15 and the previous one was H14 but they are both 8Z0 959 433 Q.

Can anyone advise on what to do to restore the remote locking function?
Click to expand...

The shop code is not relevant.

Check out the How to section - Index section. There is a post on there that explains the process.

If you have replaced the CCU for one with the same alpha code at the end (such as Q or AF) then you might be able to pair the remotes again but your free VCDS might not work. Check out the link. Adding additional keys- including the new shape key

If the alpha code at the end of the part number (on the top of the CCCU) then you might not be able to pair the keys you have (there are different frequencies) In your case they are the same so the keys will pair with your replacement CCCU

Steve B
 
You must log in or register to reply here.
Back
Top