Audi A6 dead!

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Ultra Sound Guy

Original Poster:

28,805 posts

201 months

Monday 29th January
quotequote all
Not sure if anyone can help?!
I’ve got a 2008 Audi A6 C6 LeMans edition Avant.
Yesterday I was looking for a problem with the rear wiper (didn’t remove or change anything). When I finished I tried to start the car… Nothing! Completely dead!
Then I tried to take it out of Park, it wouldn’t budge!
Ignition key wouldn’t come out! Luckily I know the trick to remove it.
Central locking doesn’t work, can only open driver’s door with key, all other doors lock.
Alarm goes off when driver’s door is opened, that seems to be the only thing which works.

Anyone have any ideas as to what can cause a major fail like this?
Is there a master fuse which could cause everything to fail?
Battery is good and holding its charge.

blueg33

38,542 posts

231 months

Monday 29th January
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Do the windows work? A long time ago my C6 Le Mans had issues with the body control module.

Also IIRC, the Avants had issues with water leaking from the rear washer system into an ECU of one sort or another.

Wonder if an OBD reader would allow you to see if there are any fault codes from ECU's?

Desiderata

2,577 posts

61 months

Monday 29th January
quotequote all
I had very similar with a 2007 Passat years ago, but I was fiddling with the front wipers. The main ECU was under the front scuttle, it had been getting soaked and corroded for years and it just took a few nudges to knacker it completely. I know a Passat and an A6 aren't the same, but they are related.

Ultra Sound Guy

Original Poster:

28,805 posts

201 months

Monday 29th January
quotequote all
blueg33 said:
Do the windows work? A long time ago my C6 Le Mans had issues with the body control module.

Also IIRC, the Avants had issues with water leaking from the rear washer system into an ECU of one sort or another.

Wonder if an OBD reader would allow you to see if there are any fault codes from ECU's?
Nothing works except the alarm.

I’ll check fo ECU modules at rear.

OBD reader throws up too many errors to be able to pinpoint the real cause.

Ultra Sound Guy

Original Poster:

28,805 posts

201 months

Monday 29th January
quotequote all
Desiderata said:
I had very similar with a 2007 Passat years ago, but I was fiddling with the front wipers. The main ECU was under the front scuttle, it had been getting soaked and corroded for years and it just took a few nudges to knacker it completely. I know a Passat and an A6 aren't the same, but they are related.
.
I was working on rear wiper. Took care of main ECU under front scuttle a couple of years back. It’s all dry and no corrosion now.

stogbandard

391 posts

57 months

Monday 29th January
quotequote all
What about the ECU under the front passenger floor is there water ingress?. Easy way to check is to lift the rear seat cushion which will allow you to slip you hand behind the carpet to the bare floor to find any water. I had an inch in mine and after stripping out the whole interior I found it was coming in from the plenum drains into the chassis rail and up through the plastic bungs which are not watertight.

Ultra Sound Guy

Original Poster:

28,805 posts

201 months

Monday 29th January
quotequote all
stogbandard said:
What about the ECU under the front passenger floor is there water ingress?. Easy way to check is to lift the rear seat cushion which will allow you to slip you hand behind the carpet to the bare floor to find any water. I had an inch in mine and after stripping out the whole interior I found it was coming in from the plenum drains into the chassis rail and up through the plastic bungs which are not watertight.
I didn’t know there was one under there!
What does it control?
Could be a little difficult as only the driver’s door will open at the moment! frown

Dr G

15,400 posts

249 months

Tuesday 30th January
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There's normally a main fuse "fusible link" on the battery, sometimes a couple of them. They look like this:



Often on or right next to the battery but I'm not familiar with their exact location on your car. Manual may tell you if you can access it.

Tom8

3,055 posts

161 months

Tuesday 30th January
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Battery failure, had exactly same with S8. Or battery lead has simply come off?

stogbandard

391 posts

57 months

Tuesday 30th January
quotequote all
Ultra Sound Guy said:
stogbandard said:
What about the ECU under the front passenger floor is there water ingress?. Easy way to check is to lift the rear seat cushion which will allow you to slip you hand behind the carpet to the bare floor to find any water. I had an inch in mine and after stripping out the whole interior I found it was coming in from the plenum drains into the chassis rail and up through the plastic bungs which are not watertight.
I didn’t know there was one under there!
What does it control?
Could be a little difficult as only the driver’s door will open at the moment! frown
There’s a massive, if old thread on this issue with the A6 C6: https://www.vwaudiforum.co.uk/forum/showthread.php...



Scabutz

8,164 posts

87 months

Tuesday 30th January
quotequote all
Ultra Sound Guy said:
stogbandard said:
What about the ECU under the front passenger floor is there water ingress?. Easy way to check is to lift the rear seat cushion which will allow you to slip you hand behind the carpet to the bare floor to find any water. I had an inch in mine and after stripping out the whole interior I found it was coming in from the plenum drains into the chassis rail and up through the plastic bungs which are not watertight.
I didn’t know there was one under there!
What does it control?
Could be a little difficult as only the driver’s door will open at the moment! frown
This is a classic A6 problem. The ECU down there is the CCM, convience control module, controls stuff like central locking.

Water leaks from the engine bay due to clogged bungs as the poster above says.

You might be able to remove it and dry it out, other wise it will need repair/replacement. Plus you'll need to deal with the ingress.

stevemcs

8,989 posts

100 months

Tuesday 30th January
quotequote all
It might just be a coincidence, the rear wiper on these is always the motor, the water from the washer jet leaks inside the motor and everything rusts.cYou can open it up and try and clean it but you usually end up replacing it. You can sometimes get the Valeo one from Euros, or genuine are £165 plus vat.

As for the other issue i'd be looking at the battery.

Ultra Sound Guy

Original Poster:

28,805 posts

201 months

Tuesday 30th January
quotequote all
stogbandard said:
Ultra Sound Guy said:
stogbandard said:
What about the ECU under the front passenger floor is there water ingress?. Easy way to check is to lift the rear seat cushion which will allow you to slip you hand behind the carpet to the bare floor to find any water. I had an inch in mine and after stripping out the whole interior I found it was coming in from the plenum drains into the chassis rail and up through the plastic bungs which are not watertight.
I didn’t know there was one under there!
What does it control?
Could be a little difficult as only the driver’s door will open at the moment! frown
There’s a massive, if old thread on this issue with the A6 C6: https://www.vwaudiforum.co.uk/forum/showthread.php...
Thanks for that, looks like I’ll be busy tomorrow, lifting carpets!

OldGermanHeaps

4,211 posts

185 months

Tuesday 30th January
quotequote all
Check in the boot for wet modules, or damaged wiring. something is likely dragging the canbus down to the point where unrelated modules cant communicate with each other. One wet or shorted module can render the whole car dead or misbehaving. Great feeling when you buy a non runner for scrap money on a punt and it turns out to be a module you can pick up for 40 quid used and code in yourself with vcds or carprog.

catso

14,853 posts

274 months

Wednesday 31st January
quotequote all
stevemcs said:
It might just be a coincidence, the rear wiper on these is always the motor, the water from the washer jet leaks inside the motor and everything rusts.cYou can open it up and try and clean it but you usually end up replacing it. You can sometimes get the Valeo one from Euros, or genuine are £165 plus vat.

As for the other issue i'd be looking at the battery.
Recently replaced the wiper motor on mine (S4 Avant) with the Valeo at around £80. The original that I removed was also Valeo. There were cheaper no-brand versions available for around £30 on ebay but I decided to avoid them.

As for the car being dead, when my wiper motor was playing up (not resetting and running on), water was also leaking from it into the boot, exactly where the battery is so I'd start by looking in there.

OldGermanHeaps

4,211 posts

185 months

Wednesday 31st January
quotequote all
catso said:
Recently replaced the wiper motor on mine (S4 Avant) with the Valeo at around £80. The original that I removed was also Valeo. There were cheaper no-brand versions available for around £30 on ebay but I decided to avoid them.

As for the car being dead, when my wiper motor was playing up (not resetting and running on), water was also leaking from it into the boot, exactly where the battery is so I'd start by looking in there.
The 30 quid ebay one i got lasyedlonger than the valeo one going by the date stamp on the valeo it failed 3 years from manufacture, my wachungho special is still good and watertight 5years on.

catso

14,853 posts

274 months

Wednesday 31st January
quotequote all
OldGermanHeaps said:
catso said:
Recently replaced the wiper motor on mine (S4 Avant) with the Valeo at around £80. The original that I removed was also Valeo. There were cheaper no-brand versions available for around £30 on ebay but I decided to avoid them.

As for the car being dead, when my wiper motor was playing up (not resetting and running on), water was also leaking from it into the boot, exactly where the battery is so I'd start by looking in there.
The 30 quid ebay one i got lasyedlonger than the valeo one going by the date stamp on the valeo it failed 3 years from manufacture, my wachungho special is still good and watertight 5years on.
Fair enough, I wasn't brave enough to try but interesting to know, maybe next time.

My original lasted 9 years BTW but low mileage and garaged which undoubtedly extended it's life.

Ultra Sound Guy

Original Poster:

28,805 posts

201 months

Wednesday 31st January
quotequote all
I looked in the boot last weekend and all was dry!
So many useful ideas put forward, which I’d like to check, but am hampered by the the fact that the only door which opens is the drivers door!
I can’t open the tailgate, so can’t get the floor panel up to gain access to the battery.
Can’t open other doors, so far from easy to remove passenger seat and carpet to check for water under there.
Problem is made worse by the fact that the neighbours are getting a little annoyed by the fact that every time I open the driver’s door the alarm goes off!
Why do manufacturers design cars which rely on electronics to open/close all but one door?!

OldGermanHeaps

4,211 posts

185 months

Thursday 1st February
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Is there not an emergency release slot you activate with a screwdriver, near the warning triangle?

Dr G

15,400 posts

249 months

Thursday 1st February
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Yup, little plastic panel inside the tailgate for exactly this scenario.