Automatic start/stop: system fault! Function unavailable

jimmydougle

Registered User
Hi all,

I've had yet another fault with my S3 this week, I think I'm on 8 now. I've had this one before and they fixed it (well might not have done now I have it again).

I turned my engine on. There was immediately a loud grinding noise coming from the engine for about 2 seconds, then this error came up on the screen: "Automatic start/stop: system fault! Function unavailable."

However, the system does sometimes work again when I turn the engine off and on again. Has anyone else had this problem? Last time I had this the dealer told me that the crank shaft sensor was broken and the car automatically shuts down other "non-essential" features of the car.
 

veeeight

I am a very pretty girl
VCDS Map User
I've had the variable cam shaft mechanism fail on my S3 at 5000 miles ish, which inhibited Pre Sense and ACC from working.

Good quality, these Audi cars ;)
 

jimmydougle

Registered User
Ah now I have that as well, perhaps it's related.

I have a list for my dealership to look at when I take it in, I'm guessing they don't like me anymore after the email I sent... The "quality" was a subject I raised.
 

Gorillajebus

Registered User
Registered myself just to tell you that I had the exact same issue.

Started my S3 in the morning and heard that grinding nose as well and the message on the screen displayed me the exact same message.
Had my dealer check it but they said this error would not be recorded in the bordcomputer which makes it hard to diagnose.
The only thing they found was an undervoltage in the on-board power supply a couple of times.
Still they couldn't tell me whether that was the reason for the start/stop failure.
 

jimmydougle

Registered User
Welcome to the forum :)

Thanks for letting me know, this is very useful. It's strange that the computer doesn't pick this up. Did they do anything to fix the undervoltage? I'm guessing you still occasionally get this fault come up if they couldn't fix it.

I wonder if Audi can be convinced to replace the start/stop device. Does anyone know if that's a possible thing to do?
 

Gorillajebus

Registered User
The only thing the dealer did was checking the battery which was healthy and fully charged.
They said they don't know what to do about it and asked me to gather more information for them if possible.

At first I thought it might be affected by the ambient temperature, but it wasn't.
From what I observed over time the failure occurred randomly.

I own the S3 for around 1 1/2 years now and this start/stop failure happened maybe 5 to 6 times.

Last time the error occurred was last week.
 

kikin

Registered User
It happens to me when:
- not driving my car for more than 2 days and it takes a little miles to get it operative again
- when driving too much time and engine is too hot.
Not sure is it a problem or just related to ambient temperature or engine.
 

HawkeyeS3

Registered User
So if you read the updates to my thread, it looks like I have a fuelling issue (no idea why, but its seriously overfuelling at tickover for some obscure reason). That aside the turbo sliders are rattling as well (apparently) so it's down at the dealers now awaiting analysis.

What they did tell me though was that any issue with the engine though will "activate" start/stop. The "get around it to get home" is to de-activate start/stop manually by turning on the switch on the dash (it's the only way we could get mine to the dealers this morning), but what it does tell me is that start/stop can mask the issue (they use it to stop the engine being damaged, which is fair enough I guess - just depends (as in my case) where it chooses to do it! The fast lane of the M25 in rush hour traffic was not the time nor the place!

So it looks like my issue was a bit different from yours possibly, however the other thing I did learn was that odd bits of software do get upgraded. The Audi Assist guy this morning wondered whether the software for controlling my upper injectors / fuel rail was updated during my last service and has caused the issue. We await the synopsis (which won't be until next Tuesday earliest)
 

Jimowl

Registered User
sorry to resurrect. I had my S3 saloon delivered yesterday - 230 mile at delivery (Brighton to Sheffield - hmmm....). Drove it 40 miles into Nottingham. Today on driving back to Sheffield through Nottingham I came to a set of lights. Stop/Start turned the engine off as it had been doing. Then it abruptly restarted and I got 'Automatic Stop/Start: system fault! Function unavailable'. I switched off the ignition then back on but no change. At the next lights I switched off, removed the key then switched back on and it was reactivated.

Do I need to be worried? 2 days old and <350 miles!!
 

veeeight

I am a very pretty girl
VCDS Map User
Yes.

ACC unavailable can be a symptom of something else not working correctly.

Get it scanned for faults.

Or it may be just a glitch.
 

SJR88

Registered User
I've had this error message come up. The car has been fine today, had fairly light use, then suddenly after parking up and switching the engine back on, it seems like the engine fan is fairly loud. No grinding sound, just the fan. It goes off when you switch the engine off and comes back on, displaying the error message each time. It's an A3 1.4 TFSI. Done 11,000 miles.

Any ideas? Don't really fancy booking it in again, it goes in every couple of months for something!
image.jpeg
 

Andyescos

Registered User
Snap, had the same message a few weeks ago, Told Audi, they didn't seem too concerned, it's not done it since.
image.jpeg
 

Andyescos

Registered User
Did you get any engine noise at the same time?
Didn't hear anything, the car's going in on Saturday to fix another issue, I was going to get them to see if it logged the issue and what caused it.
 

SJR88

Registered User
Didn't hear anything, the car's going in on Saturday to fix another issue, I was going to get them to see if it logged the issue and what caused it.
Ah right. Thanks for the advice. I'll probably book it in soon anyway, there's a rattle that's been annoying me when going over bumps! Had so many issues with this car.
 

Andyescos

Registered User
Ah right. Thanks for the advice. I'll probably book it in soon anyway, there's a rattle that's been annoying me when going over bumps! Had so many issues with this car.
join the club, this is my second as the first was rejected, this with has also had a lot of issues, sadly Audi don't seem to care.
 

kikin

Registered User
Just recognize weeks ago that this message appears always in comfort mode with my DTUK FSR on. When i remove it this week for service the S/S works always fine. Thinking if there´s an error with low battery or something like that produced by the tuning box.
 

SJR88

Registered User
join the club, this is my second as the first was rejected, this with has also had a lot of issues, sadly Audi don't seem to care.
I know, they tend to just say they can't find a fault or say it's a "characteristic", sort of make you feel like you're making it up! Good luck anyway.
 

Bittern

Registered User
Found this on a TT forum with peeps having the same issue

QUOTE: as you know I also had this problem so took into Audi Poole on Monday this week. After having the car for two days Audi told me that after discussing the fault with Audi in Germany (didn't say who), it was decided that the fault lay with the Stop/Start button itself. The button was replaced and the car was delivered home on Wednesday evening. I have driven it for the last two days and fingers crossed, the problem seems to have been resolved. UN-QUOTE

Might be worth checking this out ?
 
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Andyescos

Registered User
Well it seems the fault was due to the charcoal filters, not sure where they're located but they need replacing.
 

CybrHwk

Registered User
My Start/Stop isn't working at the moment either, but I think that's more down to the lower temperature than anything else. Haven't seen any errors on the dash or a grinding noise. It just has the A crossed out when i'm sitting at lights etc, like i've switched it off
 

Aman_Aus

Registered User
Hi All, New to this forum and even new to Audi experience.. Just bought this A3 1.4 TFSI (2013) yesterday and realized that the auto start stop function is not working. Called the dealer (toyota in this case as i bought it from them) and its booked for diagnostic on 1st May.. I am not sure how much they can do as its not their model. Can anyone suggest some checks i can do myself before 1st May. ALso, the car was with dealer for 2-3 months for sale so it hasn't been driven much as i read it in this forum that sometime this could also be the cause. no strange noise from engine as mentioned above as potential cause. Temp inside/outside is also not much different.


Also, the attached pic is taken when the car is still and just started. is it normal for the RPM gauge to be where it is i.e. 0.8? I believe some tunning might be required.. again apologies I am not fully into the automobile so parden my ignorance.


Thanks
 

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Mike Farrell

A8 Mike
Found this on a TT forum with peeps having the same issue

QUOTE: as you know I also had this problem so took into Audi Poole on Monday this week. After having the car for two days Audi told me that after discussing the fault with Audi in Germany (didn't say who), it was decided that the fault lay with the Stop/Start button itself. The button was replaced and the car was delivered home on Wednesday evening. I have driven it for the last two days and fingers crossed, the problem seems to have been resolved. UN-QUOTE

Might be worth checking this out ?
Did the fault ever come back after replacing the stop start button? I have the same problem in my 2011 A8 that I've just bought. I've run VCDS scan and have an error in the engine that will not clear and also a can bus issue with the ECU. My feeling is that this is a fault associated with a component failure somewhere and is just a case of finding it. The trouble is knowing what's most likely and unfortunately there doesn't seem to be enough people on the internet who have found a solution or have followed a structured approach to finding the root cause. I'll keep searching!
 

Audidi

Useful idiot
Maybe your battery voltage is low if it has been sitting in a dealer for a while. Give it a good run around and see if it's better after a restart.
I’ve seen this happen on my A6 Bitdi every time I use the in car media and it drains the battery.
Makes sense it will disable start/stop if battery level isn’t optimum.
 

JohnM100

Registered User
VCDS Map User
Gold Supporter
I’ve seen this happen on my A6 Bitdi every time I use the in car media and it drains the battery.
Makes sense it will disable start/stop if battery level isn’t optimum.

.....but surely that would show as the ‘A & circle’ icon but with a diagonal line through it?
 

Audidi

Useful idiot
.....but surely that would show as the ‘A & circle’ icon but with a diagonal line through it?
Only when another process is affecting the use of stop start.
In my case I meant if my MMI tells me it will soon turn off the save battery, it will then say there is a stop/start fault when first started.
 

jack666

Registered User
Hi all,

I've had yet another fault with my S3 this week, I think I'm on 8 now. I've had this one before and they fixed it (well might not have done now I have it again).

I turned my engine on. There was immediately a loud grinding noise coming from the engine for about 2 seconds, then this error came up on the screen: "Automatic start/stop: system fault! Function unavailable."

However, the system does sometimes work again when I turn the engine off and on again. Has anyone else had this problem? Last time I had this the dealer told me that the crank shaft sensor was broken and the car automatically shuts down other "non-essential" features of the car.
I have the exact same issue with the automatic start stop but I don’t get any grinding noise or anything like that? Only problem I have with the car is the system itself
 

AJa6super

New Member
Same thing just came on for me. I hooked it up and it’s saying my 2nd and 6th cylinders are misfiring.. not what I wanted to hear after buying the car a couple months ago.. Someone tell me this could just be the spark plugs or something
 
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