Cruise control / Start-stop system issue

[Pbro]

Hi , often when I start up , the dash reads : Start-stop system fault , function unavailable.

Now there is also another highly recurrent issue with cruise control. It simply will not come on when I press the CC button. I have noticed however that if I drive for a couple of minutes. Stop and turn the engine off and then restart the engine , the cruise control becomes available without fail.

There doesn’t seem to be any battery issue as car starts every time. Anybody any idea what the problem might be ? Thanks.

[Mattham]

I had similar issues, mostly with the start/stop to be fair and not the cc....it was a battery issue in the end, even though the car started no problem, the charge was constantly below the threshold at which the start stop would work. I also noticed that the mirrors would be slow to open as well when I had this issue. It took 3 goes at a dealer but in the end they replaced the battery under warranty, no issues since then.
Matt

[Pbro]

Many thanks for your reply Matt.

I suspected it may still be a battery issue. TBH the start stop has not worked in more than a year come to think of it but there was never any fault warning until recently.

Just now it faltered on starting and I had to press the start button again. Both wing mirror failed to unfold. Even after restarting they would not unfold but on restarting again, they did.

The car is no longer under warranty and the battery is over 4 years old. The dealer wanted about £100 just to investigate.

I am minded to simply replace the battery and see if the fault goes away.

[danwheatley]

I had similar issues, mostly with the start/stop to be fair and not the cc....it was a battery issue in the end, even though the car started no problem, the charge was constantly below the threshold at which the start stop would work. I also noticed that the mirrors would be slow to open as well when I had this issue. It took 3 goes at a dealer but in the end they replaced the battery under warranty, no issues since then.
Matt

I have an issue with my stop/start which I’ve posted about, along with some other things, had my battery tested but it was coming back fine at 12.6v - Really unsure what to do next !

[Pbro]

Update:

I had Audi replace the battery at the weekend. Since then , I have driven it every day to work and back , there have been no problems whatsoever.

[danwheatley]

Update:

I had Audi replace the battery at the weekend. Since then , I have driven it every day to work and back , there have been no problems whatsoever.

Did they replace like for like battery or another brand? Was it testing at over 12v before the change?

[Pbro]

Sorry I don’t know which brand it was or what it was testing as.

But the doors were a bit sluggish unlocking and the mirrors too beforehand. Now the locks are noticeably snappier.

[Mattham]

Update:

I had Audi replace the battery at the weekend. Since then , I have driven it every day to work and back , there have been no problems whatsoever.

Glad you got it sorted, I know how annoying I found it before mine was fixed

[Pbro]

Cheers mate 👍

[Waddie]

I have an issue with my stop/start which I’ve posted about, along with some other things, had my battery tested but it was coming back fine at 12.6v - Really unsure what to do next !

A fully charged battery should be around 13.8v, 12.6 is low.