chappo

Apologies for the long post in advance....

The start/stop system works only intermittently on my new Q7 (have had it about a fortnight). Sometimes it works fine (turns off the engine, green "A" shows in the DIS, starts again when foot is lifted off the brake, etc). However regularly the DIS displays the message "Start/stop system: system fault. Function unavailable."
The user manual indicates that there is a malfunction in the start/stop system, and states "Drive to a workshop soon and have the fault rectified."

After taking it to an Audi service centre, my wife was told that a full diagnostics scan indicated there was no stored fault codes, that they had seen it before on an A1 and that it should go away over time. He thought it may have something to do with the battery voltage?

Hving driven the car some more, I wondered if the message being displayed should actually be showing the "A" with the cross through it, as the cabin isn't at the prescribed aircon temp (or other usual reasons for the start/stop not to activate). We have never seen the "A" with the cross through it appear.

Has anyone else had this issue, and did it go away over time?

In case it makes a difference, it is an Australian delivered vehicle.

Thanks

zimmo

Hey chappo,

my Aussie Q7 3.0 TDI does exactly the same thing usually when a/c is on and vehicle has been in traffic (ie stopping regularly). Have had the car almost 2 months now. Not much help, but at least it's not just your vehicle.

chappo

Zimmo, sorry if I'm being daft, but do you get:
a) the "A" with the cross through it, or
b) the system fault message?
I would have thought that, if operating correctly, the "A" with the cross through it should appear.

The local dealer has said that they are following it up with Audi technical, so I'll let you know if I learn anything.

Chappo

zimmo

No problem, I wasn't very clear. I get the error message often ie start/stop system malfunction: system fault. I have never seen the green A with the cross through it on the display.

Spoke with the dealer at the time and they had not come across that error before. They did say to take it to the service centre but i chose to give it some time. IMO it happens only in situations where there is not enough reserve power when the engine is in "stop" mode to operate a/c etc.

My car has also started without me releasing the brake, whilst in stop mode during the recent hot weather (a/c was running at the time). The same error message displayed at this time. However, it did work again (ie enter stop mode) at the next set of traffic lights.

chappo

Coming back on this issue, a software update by the Audi technical team has solved the issue. Also got the reverse camera chip today and it all works - happy camper!

iconoclast

has anyone here enabled this feature on USDM Q7? any noticeable fuel savings or more of an annoyance than anything else? i had this feature on an f30 and e84 and found it to be extremely annoying but the cars are much smaller and not as thirsty as an suv. curious if this is worth enabling or just leaving it alone.

iconoclast

i had a moment to play around with settings today and "pr-7l8 start stop function" requires hardware to support the function and unfortunately cannot be enabled by coding alone.