Automatic Start stop not functioning / Error Automatic Start Stop: System Fault! Function unavailabl

[Aman_Aus]

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 other forum that sometime this could also be the cause. no strange noise from engine as mentioned in other forums 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

 

[AudiNutta]

Checks? Just book it into Audi.. still in warranty?

 

[SevenW]

Low battery voltage?
I disabled my start stop with VCDS and to do that you mess with the voltage at which Start Stop will cease to work.

 

[Aman_Aus]

Checks? Just book it into Audi.. still in warranty?

Its Nov 2013 model and 3 yrs warranty expired on Nov 16 so i am 5 months out of warranty

 

[Aman_Aus]

Low battery voltage?
I disabled my start stop with VCDS and to do that you mess with the voltage at which Start Stop will cease to work.

Is there a way to assess if its caused by low battery voltage?
what is VCDS?

 

[Audi Bairn]

The error message would be a pain, but I wish mine didn't work as it would save switching it off every time I started the car - hate it.

 

[Aman_Aus]

The error message would be a pain, but I wish mine didn't work as it would save switching it off every time I started the car - hate it.

the error message is not that painful as it only apear once when i start the car.. now alarming lights or any other message after that..

 

[RichardT]

Just a point - you can see if the car is just deciding not to stop the engine (eg engine not warmed up, aircon on full etc - lots of reasons) because you will get an autostop icon with a line through it on the DIS.
In other words, come to a complete and definite stop (foot hard on brake for a second or two) and the engine should stop or you get the above icon displayed.
There have been lots of reports on the forum about S/S not working that prove to be just it's not in "S/S mode".

 

[Aman_Aus]

Just a point - you can see if the car is just deciding not to stop the engine (eg engine not warmed up, aircon on full etc - lots of reasons) because you will get an autostop icon with a line through it on the DIS.
In other words, come to a complete and definite stop (foot hard on brake for a second or two) and the engine should stop or you get the above icon displayed.
There have been lots of reports on the forum about S/S not working that prove to be just it's not in "S/S mode".

Thanks Richard, I only get this message that the function in unavailable when i start the car and after that there no sign of symbol when i drive and stop. If i turn thr auto S/S off and then turn it on, it again display the message that its unavailable. I Dont get an icon with line through it bcoz i think car doesnt even try as the system know at the start that the function is not available. Someone pointed that it could be bcoz of low battery voltage as the car was with dealer for last 2-3 months..

 

[MrFlibble]

The start-stop system monitors loads of different things, and the engine will not stop unless everything is correct. Things that are monitored are:
bonnet open, driver's seat belt, trailer connected or not, engine temperature, ambient temperature, climate control setting, air conditioning use, windscreen defroster on, steering wheel position, reverse gear or park assist active, road slope, battery charge, power braking boost reserve, stability control/traction control mode, start-stop on-off button, automatic gearbox in manual/sport mode, drive select mode and many more.

However, if these sensors are working, but the start stop system has worked out that stopping the engine would be a bad idea, then the engine will not stop, and you will get a little crossed-out A symbol appear on the dash. You won't know why the start-stop system is not stopping the engine, just that it has decided not to stop the engine. For example, if the battery voltage is low, you just get the normal crossed-out A symbol, but you may separately get a battery warning message/light when you start the car.

The "fault" message is different. It means that the start-stop system can't decide whether it is a good idea to stop the engine, because it isn't able to get the information it needs because a sensor or connected system is faulty. This usually means that one of the other systems is faulty - for example, a faulty brake assist system which isn't sending information about power-assist reserve to the engine, will result in the "fault" message and stop-start being disabled. Similarly, a faulty trailer hitch connection, or a faulty temperature sensor in the air conditioning unit could all do similar things.

Because the stop-start system connects to so many other systems (climate control, brakes, stability control, engine, power steering, hill-hold, seat belts, park assist, etc.) this can be difficult to diagnose, because the fault can be in any of these systems. The first step in diagnosis will need a proper electronic diagnostic tool which can access all these systems.

 

[Benji34]

I had this message on Friday for the first time. I stopped, parked up and turned the engine off and went off to do what I had to do. When I started the car and drove off, stopped at traffic lights, it was working again. Maybe an early warning or something not working quite right.

 

[Aman_Aus]

The start-stop system monitors loads of different things, and the engine will not stop unless everything is correct. Things that are monitored are:
bonnet open, driver's seat belt, trailer connected or not, engine temperature, ambient temperature, climate control setting, air conditioning use, windscreen defroster on, steering wheel position, reverse gear or park assist active, road slope, battery charge, power braking boost reserve, stability control/traction control mode, start-stop on-off button, automatic gearbox in manual/sport mode, drive select mode and many more.

However, if these sensors are working, but the start stop system has worked out that stopping the engine would be a bad idea, then the engine will not stop, and you will get a little crossed-out A symbol appear on the dash. You won't know why the start-stop system is not stopping the engine, just that it has decided not to stop the engine. For example, if the battery voltage is low, you just get the normal crossed-out A symbol, but you may separately get a battery warning message/light when you start the car.

The "fault" message is different. It means that the start-stop system can't decide whether it is a good idea to stop the engine, because it isn't able to get the information it needs because a sensor or connected system is faulty. This usually means that one of the other systems is faulty - for example, a faulty brake assist system which isn't sending information about power-assist reserve to the engine, will result in the "fault" message and stop-start being disabled. Similarly, a faulty trailer hitch connection, or a faulty temperature sensor in the air conditioning unit could all do similar things.

Because the stop-start system connects to so many other systems (climate control, brakes, stability control, engine, power steering, hill-hold, seat belts, park assist, etc.) this can be difficult to diagnose, because the fault can be in any of these systems. The first step in diagnosis will need a proper electronic diagnostic tool which can access all these systems.

o wow.. now i am more certain that Toyota guys will not be able to diagnose that

 

[Jonathan Moore]

I had the same issue on my 2016 Q5 3.0T. When I bought the car the auto start stop would engage fairly regularly. At around 35k miles, it only engaged if I drove the car for at least 20 - 30 minutes and even that was rare. It got very annoying as all the conditions were right for the system to engage. To be clear there were no errors indicating a malfunctioning system, just the A with the line through it...

In my case, it turns out the system functioned much less frequently because the service interval was due on the car. I just happened to reset the Service Reminder (SRI) using VCDS and now the system engages regularly, like every time after the second or third full stop. I'm guessing the reasoning behind this is that if service is due on the vehicle, the system engages less frequently to put less strain on an engine that needs servicing.

If you're having issues with your start stop system, check to see when your next service is due, get your car serviced (make sure your garage resets your system) or just reset the Service Reminder yourself using VCDS. If you chose to do this yourself, you must use VCDS. Resetting the oil change interval in the MMI won't solve the issue.