Engine Stop Start Button Not Working

optimistique1 · Post by **optimistique1** » Wed Jun 05, 2019 4:10 pm

Does anyone have any ideas on how to fix the engine stop/start function?

Mine doesn’t seem to be working.

When I stop at the lights for example and take my foot off the clutch and depress the foot brake pedal nothing happens?

enuff_zed · Post by **enuff_zed** » Wed Jun 05, 2019 4:14 pm

Do you mean autostop doesn't work?

Is the light on or off? If it's on then you've got it deselected, but it should reset when you turn the ignition off anyway.

Bear in mind it won't work unless within certain parameters; engine warmed up, battery sufficiently charged, load sufficiently low etc.

optimistique1 · Post by **optimistique1** » Wed Jun 05, 2019 4:43 pm

No the light isn’t on so I assume it’s activated?

However, I’ve tried numerous times to use it since I go my car about two months ago and it never works?

Smartbear · Post by **Smartbear** » Wed Jun 05, 2019 5:16 pm

optimistique1 wrote: ↑Wed Jun 05, 2019 4:43 pm No the light isn’t on so I assume it’s activated?

However, I’ve tried numerous times to use it since I go my car about two months ago and it never works?

How long are your journeys? As stated above this function only works if certain criteria are met-if the engine isn’t fully up to temperature for example it will not activate

Rob

Simmocs330 · Post by **Simmocs330** » Wed Jun 05, 2019 5:57 pm

Had this on my van recently which was only 18 months old. I had to replace the battery. It would start no problem but a test revealed it was just below the threshold for the stop/start to kick in.

enuff_zed · Post by **enuff_zed** » Wed Jun 05, 2019 7:12 pm

I'd bet I'm not the only one who turns it off as soon as I get in the car?
Seems to be a lot of unnecessary wear and tear to save a few microns of pollution.
Do the same on my daily and the wife's 220D convertible too.
She always asks why I bother, but then her turbo collapsed in spectacularly noisy fashion after only 22k.
Of course it could be unrelated, but commuting round the M25 in stop/start traffic can't help, as the turbo loses its oil feed as soon as the engine stops running. I reckon it probably had to run down about 30 times a day, just for the sake of switching off the stop/start function.

optimistique1 · Post by **optimistique1** » Wed Jun 05, 2019 8:24 pm

I'm going to go for a long drive tomorrow then and let the engine fully warm up and see if that makes a differnce

Mr Tidy · Post by **Mr Tidy** » Wed Jun 05, 2019 10:06 pm

There are loads of parameters that the car monitors before deciding whether to allow it to operate.

Ambient temperature, engine temperature, battery condition, electrical load (high-drain things like Climate, HRW, etc.) being just a few.

Personally I'd be grateful it isn't working - I had a 123d with stop/start. It needed a new AGM battery in less than 5 years and 55K miles - by the time it was coded it cost over £250 at an Independent! Then before it was 7 years old at less than 77K miles it needed a starter motor that cost over £600 fitted at Sytner (I couldn't wait for an Indy as it was my only car at the time).

After that I just turned it off every time I used it!

Whereas the "normal" battery in my E86 lasted 10 years and over 80K miles - and the replacement only cost £90.

I can't help thinking stop/start is what killed the battery and starter motor - even if it does get you into a slightly lower band for road tax.

Smartbear · Post by **Smartbear** » Wed Jun 05, 2019 11:26 pm

Mr Tidy wrote: ↑Wed Jun 05, 2019 10:06 pm There are loads of parameters that the car monitors before deciding whether to allow it to operate.

Ambient temperature, engine temperature, battery condition, electrical load (high-drain things like Climate, HRW, etc.) being just a few.

Personally I'd be grateful it isn't working - I had a 123d with stop/start. It needed a new AGM battery in less than 5 years and 55K miles - by the time it was coded it cost over £250 at an Independent! Then before it was 7 years old at less than 77K miles it needed a starter motor that cost over £600 fitted at Sytner (I couldn't wait for an Indy as it was my only car at the time).

After that I just turned it off every time I used it!

Whereas the "normal" battery in my E86 lasted 10 years and over 80K miles - and the replacement only cost £90.

I can't help thinking stop/start is what killed the battery and starter motor - even if it does get you into a slightly lower band for road tax.

So the money you save on tax pays for the consumables & you save the planet as a bonus? Win win

Rob

Mr Tidy · Post by **Mr Tidy** » Wed Jun 05, 2019 11:56 pm

Smartbear wrote: ↑Wed Jun 05, 2019 11:26 pm So the money you save on tax pays for the consumables & you save the planet as a bonus? Win win
Rob

Well not quite - the pittance you save on road tax by pretending to save the planet doesn't get close to covering the cost of a new battery and starter motor!

Iain.

Nictrix · Post by **Nictrix** » Thu Jun 06, 2019 7:50 am

Mr Tidy wrote: ↑Wed Jun 05, 2019 11:56 pm
Smartbear wrote: ↑Wed Jun 05, 2019 11:26 pm So the money you save on tax pays for the consumables & you save the planet as a bonus? Win win
Rob
Well not quite - the pittance you save on road tax by pretending to save the planet doesn't get close to covering the cost of a new battery and starter motor!

Iain.

Cant even say your saving the planet when getting rid of a battery causes damage to the environment.
So a battery that last 10 years in a normal car is probably way better for the environment than a car with stop/start using 2 batteries over the same time.

kswon86 · Post by **kswon86** » Thu Jun 06, 2019 12:25 pm

check your heat/aircon is on automatic mode. I'm not quite sure for the z4 but usually it activates when it's in auto mode. if it doesn't work after the advises above, check your battery condition

gov · Post by **gov** » Thu Jun 06, 2019 1:24 pm

my bet is the battery - my wife's Sanderos Stepway ( stop laughing ) had it's first service a week or so ago - driving it back from the garage I noticed the stop/start wasn't working - phoned them and they said it was almost certainly the battery ( not fully charged ) suggested taking it for a long run - I put my trusty trickle charger on it ( it showed only 3 lights indicating it needed charging ) after a couple of hours indicator showed 5 lights and fully charged ) stop/start works again as it should

enuff_zed · Post by **enuff_zed** » Thu Jun 06, 2019 3:10 pm

gov wrote: ↑Thu Jun 06, 2019 1:24 pm my bet is the battery - my wife's Sanderos Stepway ( stop laughing ) had it's first service a week or so ago - driving it back from the garage I noticed the stop/start wasn't working - phoned them and they said it was almost certainly the battery ( not fully charged ) suggested taking it for a long run - I put my trusty trickle charger on it ( it showed only 3 lights indicating it needed charging ) after a couple of hours indicator showed 5 lights and fully charged ) stop/start works again as it should

Bet it's the constant stop/starting that is dragging the battery down

Z4-forum.com

Z4-forum.com