Start-Stop Problems

[ali00]

So I picked up my A6 BE 2.0 this week and on the day I drove it home the Start Stop function was working fine, but for these past couple of days whilst driving around the Start Stop feature hasn't been kicking in - even on long journeys. It's always been fine on any other Audi I've driven, but the 'A' symbol with a line through just stays on in the DIS.

Could it be faulty?

[johnsimcox]

It can have a bit of a mind of its own and it is hard to understand why it decides not to kick in, except obviously when the car is cold and it has only recently been started. I think air con and battery load are the two biggest reasons for it not to kick in when the car is warm, likewise it does not kick in when the car is doing a DPF regeneration. If it really is not kicking in at all then a trip to the dealer is probably the best course of action

[ali00]

I haven't had the AC on. Just the heater at a mild temperature (around 18 degrees) and low fan speed. The car has warmed up fully and still whenever i'm stationary it doesn't kick in.

Would be frustrating having to go back to the dealership after owning it for three days.

[Gwynmawr]

Sorry if dumb question, but has it been turned off - button on the dash? Even if not, is it worth toggling it on/off ?

[ali00]

Sorry if dumb question, but has it been turned off - button on the dash? Even if not, is it worth toggling it on/off ?

Its not turned off, I did turn it on and off yesterday but still no difference.

[johnsimcox]

Couple of other thoughts. It does not cut in if the Parking Sensors are activated, I also think there is a speed component in the equation, if the car has been driving very slowly before coming to a halt it won't cut in. Finally to Gwynmawr's point if the car is stationary and it has not cut in try switching it off then on with the switch on the dash.

[ali00]

The parking sensors have been off and the car hasn't been driving at slow speeds like the manual specifies. However, I will later on tonight drive around, warm the car up and then if it doesn't stop when it comes to a halt turn the Stop Start off and then on manually again.

[Wuffles]

Press the brake pedal harder. It is sensitive to whether you are fully "depressed" or not.

[ali00]

Press the brake pedal harder. It is sensitive to whether you are fully "depressed" or not.

Cheers, will also try this.

[skibuddy]

This time of year onwards mine is very intermittent. Doesn't work in the morning at all. Occasionally works in the evening. Only sure fire way to get it to operate is to turn the air con/heater unit off.

[ali00]

This time of year onwards mine is very intermittent. Doesn't work in the morning at all. Occasionally works in the evening. Only sure fire way to get it to operate is to turn the air con/heater unit off.

I don't understand why it was working perfectly on the day I picked up the car (at about 5 in the evening on Wednesday) and the heaters and electrics were all on and it was stopping and starting fine after around 5 minutes of driving - yet now even on longer journeys it's doing zilch

[Gwynmawr]

Another thought, you say you *don't* have the air con on - does this mean heaters are on all the time (no matter how low) - as Johnsimcox said, doesn't work if drawing a lot of battery power. Try diving with the AC on, so the car gets to a standard temp and the fans will then turn off. I find in the cold mornings if I'm waiting at lights for a long time it turns itself back on, and I think it is tied to the heaters kicking back in.

was the AC on on the day you collected the car? Could be the link.

[ali00]

Another thought, you say you *don't* have the air con on - does this mean heaters are on all the time (no matter how low) - as Johnsimcox said, doesn't work if drawing a lot of battery power. Try diving with the AC on, so the car gets to a standard temp and the fans will then turn off. I find in the cold mornings if I'm waiting at lights for a long time it turns itself back on, and I think it is tied to the heaters kicking back in.

was the AC on on the day you collected the car? Could be the link.

I shall try that tomorrow. But it's still funny when I drive the 2013 audi a4, that stops and starts fine even with the heaters on in this weather.

And when I collected the car the AC wasn't on, just the fan at about half speed and temp set to about 22 degrees

[skibuddy]

There must have been lots of complaints about this at my local Audi service centre because when I raised it with them to look at they gave me a printed sheet detailing all the conditions under which the stop/start would not work. Must be a unique problem to the A6 because the A5 Convertible courtesy car the gave me worked flawlessly in quite cold weather. Audi simply won't recognise there is a problem wth the A6.

[diecastsink]

I would gladly take your fault in to my car: 20 mins aux heater use, zero centigrade, two miles drive, xenon lights, seat, rear window, mirror heating on, and SS is shutting the engine down... in Feb -12 model. The best I could find is a small electric board DIY kit, which connects in parallel to switch, and makes the SS disabled few seconds after ignition is on, and THEN you can start to think green - if you like.

[a8 tech]

you can disable start stop and if you own vcds you can check the reasons the start stop was prevented from operation, its a driver assist feature for fuel consumption and doesn't take priority over cabin temp etc the list is extensive for the parameters to be all good to allow its operation

most common prevention is likely hood of misting and vehicle roll back although the amount of owners who who are unaware of the basic operation just shows the point of sale/handover is not completed

the dealers can check every occasion the system failed to function with a route cause and each model varies as does each production year depending on equipment levels etc

[Bash D Bishop]

As I said in a post a few weeks ago my SS is a bit clunky and can get caught out if I try to move off just as it is kicking in. Mine also kicks in very early from cold. A perfect example was last week. Parked overnight in a multistorey car park. Drive off and go up the exit ramp and stop a barrier to put ticket in. SS activates! :eek: This is far from an unusual occurrence.

Sent from my ASUS Transformer Pad TF700T using Tapatalk 4

[ScottyA6]

It works fine on mine. Hard down on the brake pedal seems to make the difference.

[Passatier3]

I would gladly take your fault in to my car: 20 mins aux heater use, zero centigrade, two miles drive, xenon lights, seat, rear window, mirror heating on, and SS is shutting the engine down... in Feb -12 model. The best I could find is a small electric board DIY kit, which connects in parallel to switch, and makes the SS disabled few seconds after ignition is on, and THEN you can start to think green - if you like.

Yep, first thing I do when starting the car is turn the darned thing off!

Each to his own though as it is frustrating when things don't work as intended.

[boof]

The start / stop in the A6 is certainly far more temperamental in cooler conditions than any other car I've driven with the same system.

I've always wondered if it's related to the A6 seemingly taking an age (by the dash guage) to 'warm up' in cold weather.

There are other threads on this - but I can certainly drive my 45 mins, 25 mile commute to work and never see the dash guage read the normal up to temperature reading.

If the start / stop keys off the same data that guage is displaying....

a8 tech - fascinating that the information on why it doesn't kick in is likely logged. I really wish (on all cars, not just the A6) that it would give you a dash message or otherwise have options in the centre display to relay that information to the driver easily. It would surely sort a lot of concerns out for people!

[mb500]

Hi! My two-week old A6 Allroad had the start/stop working fine for the first week but ever since it has disappeared. However at times when the start/stop should kick in, the idle speed occasionally goes haywire and the engine seems to misfire. Pushing the start/stop button stops this behaviour immediately. I have fiddled with the AC etc. but it makes no difference. It is almost as if the system can't make its mind up whether to use start/stop or not! I am about to call the dealer who I am sure will never have heard of this problem......

[Antowens]

my 2010 A4 does the same start/stop comes on when it feels like it as said it has got a mind of its own and if it doesnt want to work it wont hahaha

[johnsimcox]

mb500 what you are describing is definitely not how the S/S should work. There are many posts on this forum and others about the vagaries of the S/S system and when it chooses to activate )as suggested by Antowens), however your description suggests something different in that it is trying to activate but is unable to and keeps trying. As you have an Allroad it is clearly an automatic so it may be something as silly as the sensor on the brake pedal not working properly. Might be worth seeing if it behaves differently if you put the car in Park as that removes the brae pedal sensor from the equation (of course if the problem is by putting the car in park try just holding it on the brake pedal)

[ali00]

-Just posting an update on the issue! Since posting this thread the start stop has been working fine. It just seems to be more temperamental than any other Audi I've driven before with the start/stop feature. Car is now working perfectly :)

& as for mb500, sounds like quite a serious issue mate, i'd deffo take it round to the dealers and get it checked out - especially with it only being two weeks old.

[Goal flag]

Over the past few weeks the start-stop on my 2012 A6 would only ever kick in when I had nothing drawing power from the car, I.e. Fans, heaters, AC etc. On arrive yesterday's tried pressing the brake pedal harder when I came to a stop. Wow, what a difference. Car is now stop starting as I would expect.
For reference i used to press the brake pedal just hard enough to activate the parking brake, I'm now pressing down a tad (estimate 1") further.

[mb500]

After a long run (100 miles), the start stop did start to work again - sometimes. When it didn't, the idle speed became unstable and as before, pressing the Start/Stop disable switch cured it. It also seems that unless you give the brake pedal a good shove, the start/stop does not kick in at all. Maybe the brake pressure sensor is a bit iffy or it's something more worrying like the battery voltage threshold detection software has no hysteresis so if the battery voltage is just around the trigger point, the system gets confused. A software update required?

[diecastsink]

After SS stopping and after restarting (few occasions happened with immediate restart which does not sound good) it should not stop again until the vessel speed has come over certain limit. Obviously you have a real fault other than simple sensor failure.

[ali00]

Hi all, it will be 4 weeks since having collected the car off the dealership tomorrow and the stop start system has worked only for about 20% of the time.

I have noticed that if I cycle through turning the windscreen heater on and off it works fine after that, however, if I make a journey (be it 50 miles or 5 miles) without turning the windscreen heater on at least once, it won't kick in it all.

I was originally comparing the system to my 63 A4 which stops and starts perfectly even on 5 minute journeys but thought it may well just have something do with the A6 being a bigger car so thus taking longer for it to kick in, but that theory's gone out the window seeing as it doesn't work at all.

I don't NEED the stop start system in my life, its just quite annoying and disappointing, for me as a customer, for the car to have the system but then for it not to work - that too in a car that's done less than 600 miles.

I'll be ringing the dealer tomorrow to have it looked at, but anyone have any ideas what could be the potential cause?

[ScottyA6]

I have noticed that mine is showing the start/stop disabled display far more over the past few days and the system isn't kicking in. I am thinking the colder weather may have a bearing on this ?

[ali00]

I thought the cold weather could be suspect but when I drive my A4 its fine. I just think with me having to cycle through the heated windscreen to get it working, there may be a deeper underlying problem.

[mb500]

Hi, it seems that the problem with my A6 Allroad is that it idles at 775rpm when hot, rather than 625 like the loan car (Q5 3.0TDI) the Audi garage lent me. Looks like the start/stop system is fighting whatever is keeping the idle speed too high! The hot idle being too high also gives a lot of vibration through the steering column, something I have also complained about. Let's see if they can fix it....

[johnsimcox]

Over the past month my S/S system has also been less keen to activate and I can only put this down to the weather and the effect it has on energy sapping systems in the car. I believe (but am more than happy to be corrected!) that in addition to the engine temperature and electrical demand one of the biggest components of determining whether the S/S system activates is cabin temperature. If the system is detecting that the interior of the car needs heating (i.e. it is below the temp set on the CC system) then it will not activate the s/s system because it requires the engine to be running in order to provide heat to the car. Even after a long un it is still possible that at the moment that you stop the car and expect the system to activate the CC is in the process of needing to increase the interior temp. The post about needing to activate/deactivate the windscreen defrost to make the S/S system activate would perhaps support this as switching off the defrost may momentarily confuse the interface between the CC and S/S systems. It is also my understanding that if the auxiliary heater is activated then this too will stop the S/S system operating essentially for the same reasons as written above

[ScottyA6]

That would certainly explain why it seems less inclined to operate in the colder weather but having switched the heated rear screen on and off and with the engine temp still below normal it activated SS the next time I pulled up. I will experiment again on the way home !

[johnsimcox]

That would certainly explain why it seems less inclined to operate in the colder weather but having switched the heated rear screen on and off and with the engine temp still below normal it activated SS the next time I pulled up. I will experiment again on the way home !
Not totally sure if Ali00 meant windscreen or rear window. I took his post to mean front windscreen rather than the rear. Also be interesting to know whether those with the most problems have 2 or 4 zone CC and also what temperature they have the system set to. Mine is the 2 zone system and it is usually set to 19 and left on Auto with the AC on

[ali00]

I meant the front windscreen heater, but it may also work with the rear.

I have 2 zone climate control.


Anyway, I have had the car booked in to the dealers for the 10th - so I'll see if they come up with anything.


Don't know if it's just me, but having driven a couple of other cars with Start-Stop, the system in the A6 seems rather sloppy and kind of a 'work in progress' - unless it's just me that's ended up with a faulty one(!)

[ScottyA6]

It has been a few degrees warmer here over the past couple of days and my 245 Avant has been stop/starting like a trouper. I am sure that lower temps and electrical system loads are the determining factors in this now. After the last couple of posts I took the time to switch off various electrical systems on the car and when it was colder they made no difference. I am not saying anybody else doesn't have issues but in mine cold and load seem to determine when mine hugs a tree.

[mb500]

The Audi dealer is mystified about my A6's idle speed behaviour as there are no fault codes showing up. They have asked me to video the problem so that it can be sent to Audi for comment. However now that the car has done 1100 miles, the problem seems to be getting better. Now we just need to work on the high levels of vibration through the steering wheel at idle.... However it's averaging 46mpg, which is pretty impressive!

[mb500]

The Audi dealer has reproduced the problem on another A6 Allroad and will take up this with the factory as there is no apparent reason for it. At least it confirms that I was not imagining it!