I need to talk about Agnes !

[Seveer]

Hi,
Agnes is my wife's 2002 1.4 TDI 75 BHP A2, a little bit shabby (the A2 not my wife) but she likes her.

Agnes has had an ongoing issue for a number of years now which after discussions on here the general consensus was a CCCU isuue. The faults are central locking failing, electric windows failing, climate unit failing (main issue), petrol cap release failing, radio staying on after engine off and key removed etc etc. I was discussing getting the CCCU fixed with Timmus many years ago but at the time, there was a little bit of shenanigans going off with the service offered by Lau in Germany and one thing led to another and it didn't happen.

Now these issues were intermittent and the wife appeared to put up with them so I turned my attentions to other things and left well alone. However, it is now the norm for these things not to be working and Agnes is now becoming unsafe to drive.

I spotted a working CCCU unit for sale in the market section from a fellow member (Tomsk) it was the same variant as ours, a Q and came with a key fob ... I bought it hoping that a working unit would be the answer to Agnes' woes. After fitting it however the issues appear to remain and I am at a bit of a loss. I have read countless posts on A2OC regarding similar issues and have developed a bit of 'snow-blindness' with the amount of information I have tried to take in.

Hopefully you good people will be able to help resolve Agnes' issues and subsequently prompt me in to spending a bit of money to make her look beautiful again and a pleasure for my wife to drive rather than a chore.

I appreciate that random electrical issues can be a pain to diagnose but I am hoping that someone on here may just have the nugget of information I need to move forward. I assume the 1st step on the way forward is to get a scan done ... anyone on here local to Rotherham who wouldn't mind helping?

Many thanks in advance
Seveer

p.s when I swapped the CCCU the radio went in to 'safe mode' bit of a pain as I hadn't considered this and we do not have the code ... however, after two days of saying 'safe' on the screen the radio has come back to life and is working fine ... weird or normal ??

 

[DJ 190]

I would have thought that there can't be anyone better to sort this out than Tom (Timmus). I think that I'd be prepared to pay him for just a social visit! LOL!

David

 

[sciroccorrado]

The Q version of the CCCU is notoriously error prone. The reliable one is the one that ends in AF. These very rarely go wrong. If you fancied a trip down the M1 I have one available at the moment (see marketplace) and we could perhaps try it out here. I can do a scan for you at the same time. I'm in North Leicestershire.

As to the radio code, bit of an odd one that. I couldn't explain why it came back without you entering the correct code. However, this code may be found if you still have the radio manual it is usually on the front cover.

 

[Andrew]

I asked a question in March about the radio code. The answer was this; the radio remembers the VIN number of the car in which it was last resident. When you turn on the radio it checks the VIN, if correct it functions as normal, if a different VIN it asks for the code.

I also remember very vaguely (could be wrong) that earlier radios after power has been lost for a while (eg. fuse/battery disconnection) always ask for the code when power is reinstated, while later radios simply read and check the VIN as above.

Regardless, the radio does not wait two days to read the VIN, this is absurd and its behaviour is a side effect of your larger electrical gremlin(s) and I expect will go away when your probable CCCU fault is sorted.

Echo you need Tom.

Andy

 

[audifan]

While a lot of problems could well be down to a bad CCCU I would check ALL the earth points on the car and the earth strap itself. How good is your battery, you would be surprised just how many electrical problems are resolved by ensuring the car has a GOOD power supply and earths. Check all relevant fuses using a meter not by eye as I have seen fuses that look ok and are blown. Contact corrosion is another issue the A2 suffers from especially when there is water in the CCCU and boot. For CCCU problems @timmus . Canbus cars and there audio are linked to the vehicle and normally "desafe" quickly, pre canbus need code if I remember correctly.

 

[Seveer]

The Q version of the CCCU is notoriously error prone. The reliable one is the one that ends in AF. These very rarely go wrong. If you fancied a trip down the M1 I have one available at the moment (see marketplace) and we could perhaps try it out here. I can do a scan for you at the same time. I'm in North Leicestershire.

As to the radio code, bit of an odd one that. I couldn't explain why it came back without you entering the correct code. However, this code may be found if you still have the radio manual it is usually on the front cover.

Thank you for taking the time to reply ...

I spotted your AF version this morning and was about to PM you about it but I wasn’t sure I wouldn’t be throwing good money after bad. If fitting the AF version would bring things back to life then it’s worth every penny. I appreciate your offer of a ‘scan & try’ what days / times would be good for you?

We have all of the original manuals but inside the radio one there is a square missing which I assume had the code on it originally.

 

[Seveer]

While a lot of problems could well be down to a bad CCCU I would check ALL the earth points on the car and the earth strap itself. How good is your battery, you would be surprised just how many electrical problems are resolved by ensuring the car has a GOOD power supply and earths. Check all relevant fuses using a meter not by eye as I have seen fuses that look ok and are blown. Contact corrosion is another issue the A2 suffers from especially when there is water in the CCCU and boot. For CCCU problems @timmus . Canbus cars and there audio are linked to the vehicle and normally "desafe" quickly, pre canbus need code if I remember correctly.

Thanks for the reply,

We did have an issue with intermittent starting a while ago which turned out to be the earth behind the passenger headlamp. Other than that I haven’t checked any other earth points. I have gone through the fuses by eye and all seem ok, maybe I should invest in a meter.

 

[audifan]

Yes headlight earth is a common issue, but so is the main earth lead from the battery failing.

 

[Seveer]

Would an earth issue cause the climate unit to completely lose power for hours or days on end and then start working again ... before ultimately losing power again ?

 

[Andrew]

Would an earth issue cause the climate unit to completely lose power for hours or days on end and then start working again ... before ultimately losing power again ?

I would imagine the answer would be yes, after all the earth in a car is not the earth of your household electrical wiring but a section of the other half of a circuit. Vibration/thermal expansion/body flexing might just be enough to reinstate the circuit at the earthing pointing on a sporadic basis. Your problem may well not be an earthing problem but it would do no harm to check and it costs nothing. Do not rely on an earth check with the naked eye, reports of visually okay earth points working again when cleaned up - I magine an insulating corrosion layer a few microns thick and invisible to the naked eye would be sufficient to cause a bad earth. A bad earth near the headlight tends to cause engine related faults, for the CCCU I would focus on the earthing point because of its proximity at the base of the B(?)-pillar, the first picture in this helpful post#1 by Sarge.

https://www.a2oc.net/community/index.php?threads/electrical-a2-earth-points.8294/#post-84166

Andy

 

[Seveer]

I would imagine the answer would be yes, after all the earth in a car is not the earth of your household electrical wiring but the other half of a circuit. Vibration/thermal expansion/body flexing might just be enough to reinstate the circuit at the earthing pointing on a sporadic basis. Your problem may well not be an earthing problem but it would do no harm to check and it costs nothing. Do not rely on an earth check with the naked eye, reports of visually okay earth points working again when cleaned up - I magine an insulating corrosion layer a few microns thick and invisible to the naked eye would be sufficient to cause a bad earth. A bad earth near the headlight tends to cause engine related faults, for the CCCU I would focus on the earthing point because of its proximity at the base of the B(?)-pillar, the first picture in this helpful post#1 by Sarge.

https://www.a2oc.net/community/index.php?threads/electrical-a2-earth-points.8294/#post-84166

Andy

Sounds reasonable to me so earth point hunting is what I will be up to this weekend.

Should the battery be disconnected whilst fiddling with earth points ?

 

[sciroccorrado]

Thank you for taking the time to reply ...

I spotted your AF version this morning and was about to PM you about it but I wasn’t sure I wouldn’t be throwing good money after bad. If fitting the AF version would bring things back to life then it’s worth every penny. I appreciate your offer of a ‘scan & try’ what days / times would be good for you?

We have all of the original manuals but inside the radio one there is a square missing which I assume had the code on it originally.

Weekends are usually good for me, if you want to PM me we can swap details.

 

[Away with the fairys]

Sounds reasonable to me so earth point hunting is what I will be up to this weekend.

Should the battery be disconnected whilst fiddling with earth points ?

When prating about on any car electrical stuff , always disconnect the battery , both the positive and the negative, have a cup of tea before starting any works , move both cables well away from the battery .... it is amazing easy to upset the cars electrical kit , leading to fault lights , and other unwanted stuff, by doing this battery disconnect your working " safe" .

 

[Gary - G]

I had a similar issue a few years ago, when I owned an A6 Allroad.

The A6 was way more complicated, but I guess that it must be similar to the A2 in some ways.

I had a problem with the rear interior light and replaced it with a second hand one.

After that, the car wouldn't run, the side lights wouldn't turn off and there were all kinds of other random faults.

The solution was to disconnect both battery leads and then hold the cable ends together for 10 to 15 seconds.

After reconnecting, all was normal again....

 

[Seveer]

When prating about on any car electrical stuff , always disconnect the battery , both the positive and the negative, have a cup of tea before starting any works , move both cables well away from the battery .... it is amazing easy to upset the cars electrical kit , leading to fault lights , and other unwanted stuff, by doing this battery disconnect your working " safe" .

Again, it makes perfect sense to do as you suggest, but I thought it better to ask. I’m no mechanic and at the moment I am subscribing to the ‘act daft’ method

 

[Seveer]

I had a similar issue a few years ago, when I owned an A6 Allroad.

The A6 was way more complicated, but I guess that it must be similar to the A2 in some ways.

I had a problem with the rear interior light and replaced it with a second hand one.

After that, the car wouldn't run, the side lights wouldn't turn off and there were all kinds of other random faults.

The solution was to disconnect both battery leads and then hold the cable ends together for 10 to 15 seconds.

After reconnecting, all was normal again....

I will give anything a go, but what does holding the battery cable ends together do ?

 

[Pinkythelabrat]

I will give anything a go, but what does holding the battery cable ends together do ?

It would complete the circuit which may allow charge to move from certain circuits. I’ve never looked at the electrical science behind it but I, possibly wrongly, assumed that it would speed the discharge of capacitor-held charges. I usually disconnect a pc power supply and push the power button a couple of times for a similar reason. Just a vague belief is enough for me!


Sent from my iPhone using Tapatalk

 

[Seveer]

Right, I’ve taken the lower A-pillar trims off both sides to expose the earth connections. The drivers side has 2 earth cables and looks untouched and factory fresh. The passenger side has 1 earth cable and looks like it has been ‘fiddled with’ at some point. See photos.

I assume there is not much point in disturbing the drivers side earths but tomorrow I will check the passenger side (bit dark and cold now)

There are a multitude of connectors on both sides, is there any mileage in checking any of these ?

Seveer

 

[audifan]

As you are already there it makes sense to check everything while it is exposed. I would remove and clean both earths and also unplug each connection in turn checking for any damage or corrosion and then plug and unplug them a couple of times to "wipe" the contact faces in the plugs / sockets. Once you have done that you can rule out those areas. Under the passenger floor where the CCCU is located there are loads of connectors and relays so worth checking there also. Also good to verify the earth points are actually earthed using a meter and long leads directly onto battery earth terminal. If you look at the wiring diagram for the car especially the circuits that contain your problems you will see connectors they pass through and their respective earth points. The a2 has its own electrical problems rarely seen on other vehicles due to its aluminium construction and battery and thus circuit voltage is far more important. Any area you find damp or corrosion will need to be sorted. Have you checked the battery terminals and the main earth leads yet?

 

[Seveer]

UPDATE ...

This morning I disconnected the battery (both terminals) and set about cleaning the earth connections on the lower A-pillar. To be honest it looked fine already, clean dry & tight. I decided against tackling to drivers side one as this still looked factory fresh and also clean,dry & tight.

I also went through the fuse box under the dash and checked any for visible signs if damage; all ok. I did clean the blades on the relevant fuses (36 & 38) and swapped those for working ones from other locations ... then reconnected the battery.

Everything worked, climate unit all lit up and blowing a gale, radio on and electric windows going up and down. Left the car idling for 15 mins while I cycled through the different modes on the unit then took her for a spin ... 5 minutes later the climate unit went blank and the blowing stopped. When I parked up and turned off the ignition, the radio stayed on and the central locking wasn’t working. Electric windows still worked though !!

All of the ‘faulty’ components obviously work when the conditions are right but then something is tripping them out ... Relay possibly.

Seveer