Can anybody help? I bought this car and I drove for around 15 days after that when the car reached normal temperature all the communication faults u code and disingages the gearbox if you let the engine cool down the car starts working again. If anybody has any information about this problem could you please help thank you.

If you bought it from a dealer in the last 30 days take it back and let him sort it out at no cost to you.

On the other hand if you bought it privately and are responsible for repairs the first step is to get the battery professionally tested. A dying battery can cause the sort of faults you experienced.

Let us know the outcome.

I bought it privately and I tried to get a refund but I was unsuccessful and then I booked an Audi dealer diagnosistic but just on the 3rd of march until then I have to park it. Thank you for your reply. In the meantime I'm going to test the battery and I'll let you know.

A simple multi meter voltage test will be no good. It needs a professional one on deep discharge equipment. Most Halfords and Kwikfit (pardon me for swearing) will do it at no charge.

Thanks for the advice I will try to take one of these garages Kwik fit or Halfords so that they can do the checks for this vehicle. Because the fault just appears when the vehicle reaches the operation temperature can it be related to the temperature sensor? Thank you.

The battery has been checked and is fine; I'm now waiting to go to Audi, which is scheduled for March 3rd. 

I saw someone selling the same car as mine with the same problem. I spoke to the owner, but he doesn't know what the problem is either. 

Edited February 16Feb 16 by Toni santo

3 hours ago, Toni santo said:

I saw someone selling the same car as mine with the same problem. I spoke to the owner, but he doesn't know what the problem is either. 

Hi it may well be down to lack of gearbox servicing, most people don't bother and prefer to cling to the much spouted Audi theory that the gearboxes are filled for life, whereas most gearbox specialists will tell you oil and filters changed every thirty thousand or three years, 

Steve.

Hello everybody, a quick update relating the problem about the Audi a6 c7 I just decided to buy a new battery and fit it and for to my surprise and all the warning on the dashboard and canbuz communication problems are gone you guys are right. Thank you so much you guys are stars

New battery coded to car?

I guess the clowns at Halfords/Kwikfit didn't test it properly. I shall not be recommending them again.

Yes, I bought a new battery and asked a colleague who has Obdeleven to register it, and all the communication problems disappeared. 

Thanks Antonio,

Great news. 
For clarity, can we revert back to your post of 16th Feb. when you say ‘The battery has been checked and is fine…..’ 

Who tested it, and how was the check carried out?

Regards,

Gareth. 

I'm a truck driver, and my company has a mechanic who checked everything, including the electrical wiring. He told me he checked the battery and it was fine, but he gave a diagnosis. Wrong 

Edited February 26Feb 26 by Toni santo

It's always extremely difficult to pursuade people that a battery can be defective when it still cranks the engine normally, and has a voltage of 12.4 at rest.

9 hours ago, Toni santo said:

I'm a truck driver, and my company has a mechanic who checked everything, including the electrical wiring. He told me he checked the battery and it was fine, but he gave a diagnosis. Wrong 

World of difference between truck and an Audi which most models can be a right tart when it comes to voltage stability.

Steve.