Electrical Issues/Battery Drain

James23

Member
Hi all
I've had an A2 since 2007, and there have been 2 A2s in the family since 2008, so as you can imagine I've experienced most of the common faults with A2s.
On my sister's car - a 2003 1.4 TDI 75 (AMF) I'm experiencing a battery drain which is very inconvenient as she doesn't have off street parking so I have to keep going round and taking the battery out and putting it on charge and then go round again to reinstall when it's done.
It lasts about 4/5 days of not being used before it won't start.
It has the original Audi stereo fitted.

I've done a VCDS scan and it originally showed 4 fault codes for the climate control, but on clearing them and running the output test a few times it left only one code - 00727 - potentiometer in positioning motor for defrost flap (g135) 30-00 open or short to plus
(And when the key is in position 2 you can hear the climate control doing something)
But I'm not convinced it's related to the battery drain.

When you turn the key to position 2, the central locking sounds like it locks and unlocks all the doors.
My A2 does not do this.
I was hoping vcds would show that one of the door microswitches is faulty but no such luck.
I've opened each door in turn and each one of them puts the courtesy light on as expected and it goes off after you close each door.

I'm not sure if this fault is related to the battery drain or not but after searching on here it seems that a few members have had parasitic drains and found them to be caused by a door module.

The CCCU is an "AF" model. Which is the same as it is on my A2.

The battery has been tested at Halfords and came back as very good

The alternator is charging
Unfortunately my own A2 has recently been scrapped due to it being written off by insurance, but I broke it for spares so still have many parts left that I can swap and test.

My next steps are:

Swap the CCCU and see if it solves the problem

Measure the current draw by taking the positive terminal off and fitting my multi meter in line and waiting for the car to go to sleep and then pull fuses out one by on and record what happens. I'll probably also take the door card off and unplug each door module and see if that makes a difference.

Any hints/tips/other ideas?

Thanks

James
 

depronman

Member
Hi all
I've had an A2 since 2007, and there have been 2 A2s in the family since 2008, so as you can imagine I've experienced most of the common faults with A2s.
On my sister's car - a 2003 1.4 TDI 75 (AMF) I'm experiencing a battery drain which is very inconvenient as she doesn't have off street parking so I have to keep going round and taking the battery out and putting it on charge and then go round again to reinstall when it's done.
It lasts about 4/5 days of not being used before it won't start.
It has the original Audi stereo fitted.

I've done a VCDS scan and it originally showed 4 fault codes for the climate control, but on clearing them and running the output test a few times it left only one code - 00727 - potentiometer in positioning motor for defrost flap (g135) 30-00 open or short to plus
(And when the key is in position 2 you can hear the climate control doing something)
But I'm not convinced it's related to the battery drain.

When you turn the key to position 2, the central locking sounds like it locks and unlocks all the doors.
My A2 does not do this.
I was hoping vcds would show that one of the door microswitches is faulty but no such luck.
I've opened each door in turn and each one of them puts the courtesy light on as expected and it goes off after you close each door.

I'm not sure if this fault is related to the battery drain or not but after searching on here it seems that a few members have had parasitic drains and found them to be caused by a door module.

The CCCU is an "AF" model. Which is the same as it is on my A2.

The battery has been tested at Halfords and came back as very good

The alternator is charging
Unfortunately my own A2 has recently been scrapped due to it being written off by insurance, but I broke it for spares so still have many parts left that I can swap and test.

My next steps are:

Swap the CCCU and see if it solves the problem

Measure the current draw by taking the positive terminal off and fitting my multi meter in line and waiting for the car to go to sleep and then pull fuses out one by on and record what happens. I'll probably also take the door card off and unplug each door module and see if that makes a difference.

Any hints/tips/other ideas?

Thanks

James

I think you have exactly the right approach to diagnosing the drain
Good luck

Paul


Sent from my iPhone using Tapatalk
 

audifan

A2OC Donor
Temporarily you could remove the battery and charge it. When you put it back in the car DO NOT reconnect the leads until she is actually going to use the car. Agree completely with Paul in your approach to finding the issue.
A self contained jump pack either onto the battery terminals or a cigarette socket but not the plain jump leads that require another vehicle is a very useful thing to own especially coming towards winter, plus she could do it on her own.
 
Totally the right diagnosis approach. There's a thread somewhere about taking fuses out and measuring current drain with everything off - should be ~50mA max. I bought a clamp meter (only about £10 from ebay) which allows you to measure current while the battery is still connected. From that I diagnosed a knackered CCCU (current drain >0.5A). From memory I removed fuse 42 and current drain dropped to 50mA, but then the boot won't open as that fuse seems to operate the boot solenoid.

search for CCCU / current drain / fuses etc.
 

RAB

Technical Specialist 1.2 TDI
If you choose a clamp meter, make sure that it can measure to at least two decimal places, i.e. 0.01A or 10mA.

RAB
 
I also have current drain and my door locks do the castanets rattle after locking or unlocking as well so your door lock theory may be good.

I’ll get to sorting it out at some point but, to prevent battery damage, I fitted a solar panel on the dashboard and into the 12v accessory socket which is always live.

It has a charge controller and is a 50w panel but I already had these parts available so probably not as good an option for you as just finding the cause.

I look forward to hearing how you get on but checking the door modules does seem a sound next step.


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James23

Member
Thanks for the replies everyone. I'm almost looking forward to sorting it out now 😁
I do have a clamp meter but it doesn't do many (if any) decimal places so will use my normal multimeter.
 

mjsbrabus

A2OC Donor
Interesting.

To add to the comments above, my A2 also makes the unlocking clicks when the ignition is turned on. Is this not normal? It has always done it during my ownership. The clicks on mine seem to come only from the back doors / tailgate.

My car also appears to have a current drain (though it has sat unused for quite a long period so initially I just put this down to 'normal' battery
discharge through lack of use.

Be interested to hear what you diagnose.
 

Vic

Member
The unlocking clicks are most likely due to faulty door lock microswitch which is in door lock mechanism. Every door has its own so it is normal that sound comes only from faulty one.
 

mjsbrabus

A2OC Donor
Checked my own today and the loud clicks that come when the ignition is switched on are from BOTH back doors (but not the tailgate).

Given the improbability of both back door micro-switches going faulty at the same time, is this likely to be a CCCU related fault?
 

Alan_uk

Member
If it's any consolation just seen this YT video about a chap who has one of the first ID.3. He has a dead 12V battery after leaving the car 3 days. VW says it's a software fault. Dealer says cannot see to it for 2 weeks (presumably due to Covid-19). To make matters worse, the vehicle is trapped inside a small garage. In the end he bought a battery booster for Euro 50. Manages to start the car and gets loads of error messages telling not to drive the car.

There is some advantages in having 20 year old technology, especially when the A2 doesn't look 20 years old.

 

mjsbrabus

A2OC Donor
Well VW are supposed to have nicked all the i3 engineers from BMW to develop the ID3. Maybe they took the wrong ones?

At this stage the car does seem to have a number of software issues. BMW have had 7 years to iron them out of the i3.
 

James23

Member
I haven't yet as a different issue popped up on the car. It wasn't reacting to the ignition switch, so after replacing the ignition switch, and then the ignition barrel I re-did the earth's that I did a few years ago and added an extra engine earth and it seems to have solved that problem for now. So I ended up doing that instead of investigating this issue.
I will report back when I do though as I hate it when people don't conclude their threads.
 

dieselfan

A2OC Donor
Swap the CCCU and see if it solves the problem
Measure the current draw by taking the positive terminal off and fitting my multi meter in line and waiting for the car to go to sleep
Then pull fuses out one by on and record what happens.
(edited by me)

My 2001 AMF has a discharge /drain of 0.78A
The owner of this car is a disaster with electrical problems...
1- How long does it take for the A2 to go to sleep?
2- Is a draw above 5mA to be seen as an issue?
3- All my A2s seems to have an isse with to high current draw, I have lost (or cannot remember) that the CCCU is a common failure, right now I wonder if I have 6x CCCUs with an error... Can I test the current draw at the battery terminals WITHOUT having the CCCU installed?

Cheers
dieselfan
 
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Ami

A2OC Donor
You can measure the current drawn by the car using an ammeter in series with the positive, see what current is being drawn when car is not running.
Cheers,
Ami
How-to-use-Multimeter-to-Measure-Current.png
 

Ami

A2OC Donor
I haven't yet as a different issue popped up on the car. It wasn't reacting to the ignition switch, so after replacing the ignition switch, and then the ignition barrel I re-did the earth's that I did a few years ago and added an extra engine earth and it seems to have solved that problem for now. So I ended up doing that instead of investigating this issue.
I will report back when I do though as I hate it when people don't conclude their threads.
Sorry @James23 did,nt realise you already mentioned the test. :oops: only ever read the latest tread;)
 

dieselfan

A2OC Donor
Thank you @Ami , CCCP is corrected to CCCU. In my case the current draw is measured exactly as per your illustration.
Cheers
dieselfan
 
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