Hi

My wife’s Audi 3.0 v6 TDi Quattro has been doing some strange things recently. Here are the main issues; 

saying Tires under inflated 
Stabilisation control (ESG) fault
Parking brake 
Fault in braking system - contact workshop
Headlight something, can’t remember exactly what

Also happens: Steering heavy when trying to reverse, reverse camera didn’t work. 
When it starts flashing all the warning signs, the car revs change, I can hear the engine changes, it runs differently. 

Today: Speedometer kept dropping to 0 when driving, then rapidly moving up to 40 then back to 0.

The car has been steadily getting more and more faults. Our Audi specialist mechanic thought it was the battery, so that has been replaced and coded. This solved the problem for about 2 days. Then it has become worse. 
I have read it could be a faulty main ecu? I have had a look at it and the outer box is very corroded, by the windscreen drain valve side. 

Can anyone help? Is it worth trying to open the ecu to see if there is any damage internally? Eg water ingress? I’ve seen you can purchase special bolts to open the ecu. 
 

Any advise would be very much appreciated. My wife is upset and I have 3 young children. I’m worried it will brake down in a dangerous situation. At the moment it hasn’t done that. 
 

Many Thanks 

I had this. It was the ABS sensor on one wheel. 

Hello Rich,

All these symptoms could be a classic case of battery issues, and we note that that was renewed ( make?) and it it reduce the problems for a little while. 
What I would ask is - was the alternator output also checked at the same time? If not, then it’s certainly worth a low cost testing elimination before moving on. 
Kind regards,

Gareth. 

 

11 hours ago, ThomasG said:

I had this. It was the ABS sensor on one wheel. 

Thanks Garath

I am going to take it to my Audi specialist tomorrow, I will ask them to try and check the abs sensor. I appreciate your advice. 

9 hours ago, Magnet said:

Hello Rich,

All these symptoms could be a classic case of battery issues, and we note that that was renewed ( make?) and it it reduce the problems for a little while. 
What I would ask is - was the alternator output also checked at the same time? If not, then it’s certainly worth a low cost testing elimination before moving on. 
Kind regards,

Gareth. 

Yeah, that’s what we thought when the problems started to happen. So I had the battery checked and it was the original battery that came with the car. 2012.. it was changed with a Bosch battery exactly the same as what was installed.  
Yes the car was fine for 4-5 days. Then Lots of faults came back. 
I then took it to an Audi specialist who said it was because the battery wasn’t coded properly.  My wife collected the car and then the faults popped up straight away the same day. 
It was the bank holiday weekend so I haven’t had chance to speak to the Audi specialist again. 
The engine management light is also on. It’s running pretty rough as well. 
I will ask them about the alternator check. 
thanks for your advice Garath. 
The car has been so reliable up till now. 

1 minute ago, Richie102030 said:

Yeah, that’s what we thought when the problems started to happen. So I had the battery checked and it was the original battery that came with the car. 2012.. it was changed with a Bosch battery exactly the same as what was installed.  
Yes the car was fine for 4-5 days. Then Lots of faults came back. 
I then took it to an Audi specialist who said it was because the battery wasn’t coded properly.  My wife collected the car and then the faults popped up straight away the same day. 
It was the bank holiday weekend so I haven’t had chance to speak to the Audi specialist again. 
The engine management light is also on. It’s running pretty rough as well. 
I will ask them about the alternator check. 
thanks for your advice Garath. 
The car has been so reliable up till now. 

 

11 hours ago, ThomasG said:

I had this. It was the ABS sensor on one wheel. 

 

11 hours ago, ThomasG said:

I had this. It was the ABS sensor on one wheel. 

Cheers Thomas

I did read about the know abs issues with this car. I will get my mechanic to check it. 

Many thanks 

9 hours ago, Magnet said:

Hello Rich,

All these symptoms could be a classic case of battery issues, and we note that that was renewed ( make?) and it it reduce the problems for a little while. 
What I would ask is - was the alternator output also checked at the same time? If not, then it’s certainly worth a low cost testing elimination before moving on. 
Kind regards,

Gareth. 

Hi again Gareth 

🤦🏼‍♂️ My wife has just informed me that when the garage changed the battery they checked the old one and it had 55% left in the battery but it was only charging 10%. Please tell me if I’m wrong but I think you are right in saying the alternator is not charging the battery properly? I’m wondering why the garage didn’t say it could be alternator related? They just swapped the battery and it worked for a few days and then lost charge. 
 

If you invest in the OBDEleven you can scan the car for faults yourself. That's how I discovered this was the ABS sensor in my case. In fact it's been amazing at sorting all problems. 

Your garage may scan for free...

The rough engine is another matter though. But a scan will at least point you in the right direction. 

Hello Rich,

’….had 55% left (in battery)….’ probably means it was only 55% efficient compared to its original efficiency, rather than 55% ‘left’. 
A lot of battery efficiency testing meters can now be too basic for testing all (in caps) the parameters necessary to test to ensure the battery is fully up to the job it has to do, in this era of  vehicles fitted with Battery Condition Monitors. 
We have to assume that they renewed the battery with an absolute like for like in respect of the battery that you know (in caps) was fitted to the car when new. 
It could be expected that they would have carried out the simple alternator output check - but possibly not.

’…only charging 10%…’ - apologies but I don’t understand that statement.

The situation as I see it ( with the assumption that the replacement battery is the correct fitment and is itself serviceable and has been coded to the car):-

The alternator output is below par-? and/or
The car is suffering from a parasitic drain. 

I would want to (cheaply) eliminate both possibilities, before considering any other more expensive investigations and fitting of replacement parts. 
Kind regards,

Gareth.

Did you get to the bottom of this?