Stop Start Auto Start Up

[PaulTheo]

Hi,

Today on several occasions while stopped with my foot off the clutch and the engine shut down using the stop/start. The engine restarted itself without me putting my foot on the clutch. Has anyone else had this? The engine had not been stopped for more than about a minute, no major power use items on or heater requirement as we had been on the move for about 2 hours. Also the crossed out A was not lit up in the DIS.
This does not seem right?

Edit:

And no fault codes!

 

[eno394]

Still trying to work mine out. Noticed it hadn't cut out for a few weeks despite normal driving conditions, when it had previously kicked in.

Looked to see what had changed since and it was the driver fan blower speed had been set at 11 from 6. Turned it back to 6 and the car now stops again!! Also got caught out when the auto stop had turned off completely after being sat for a few mins at a level crossing. You then have to restart using the key and clutch as normal.

It has as you've mentioned started again without me being near the clutch, suppose there are just far too many factors to figure out why and the computer just does it for us?

 

[PaulTheo]

Thanks I thought the clutch had to be in for the engine to start like a safety interlock, but as the car knows it is in neutral that may not be the case just seemed a bit odd. The heating was in auto with the A/C off in econ as it was not needed. I travelled over 500 miles yesterday over to Belgium and back so plenty of running time for the battery to be fully charged and all systems at normal temps the car was great on the run though.

 

[irnbru]

Like Eno I've had some interesting things happen. I've had my my2010 car a month now and on three occasions the start stop hasn't wanted to restart. The last time I noticed the car said start stop has been disabled, please restart the car with the fob. It may have said this previously but the first couple of times I assumed I must have done something wrong.

A couple of these times I've been in heavy traffic at lights after coming off a motorway and when I've tried to restart with the key it's taken a two or three attempts for the engine to start which is pretty embarrassing with a queue behind you. Ive lost all confidence in it.

I'm guessing this isn't normal. Any ideas as to what the fault could be? I've noticed posts on A3s and A6s as well with this issue. It sounds worryingly common.

 

[Daggerit]

As far as I know the stop-start system has a set of fairly strict set of criteria it follows regarding when it will and will not function. Things like power usage, battery voltage, DPF regen cycles, water temperature, oil temperature, etc. all play a part. It could be that the fan was just pulling more power than it was happy continuing when switched off or any of the other things

I've never had any issue with an error appearing on the dash or the car not restarting though, that sounds like it might be something to get looked at...

 

[rosscotdi]

I've also found incline/ decline of car, steering wheel position, outside temp and if you have just reversed to a stop for some reason

 

[irnbru]

Funnily enough rossco each time I've had a problem the car had been titled backwards facing up a slight incline at traffic lights.

 

[richlean]

Mine restarted unexpectedly today. I'd stopped at the station to drop the Mrs off, and the engine had cut as one would expect. She was just getting her bag out of the boot when it restarted - bit of a surprise. Maybe the opening of the doors had cooled down the interior enough to justify a restart.
I've read the criteria for automatically cancelling start stop in the manual, but half the time I still can't really predict whether it will stop or not.

 

[Ceebee]

Also restarts if the steering wheel is moved at all, presume it thinks that steering wheel being moved will require power so better startup.

 

[Zafi]

I had an auto for a couple of days. If you put the handbrake on as soon as you come to a stop (like at traffic lights or a junction) the engine kept running. Just hold it on the footbrake and it stops.