This must be common topic, but I can't find it.  I believe that to make the stop start system work after changing the battery you need to reset the bms.  How do you do this without using diagnostic software?

Ignition on,
Sidelights on,
Press rear fog light button 5 times (the bottom one of the two),
Press hazard button 3 times,
Give it a few seconds and the battery light on the instrument cluster should blink a few times.

Many thanks. Just tried it, and the auto stop/start now works a treat! Thanks again.

John

10 minutes ago, John916 said:

auto stop/start now works a treat!

if it's something that you like then enjoy it while you can, I expect by this time next month it will once again have stopped working.

22 minutes ago, unofix said:

if it's something that you like then enjoy it while you can, I expect by this time next month it will once again have stopped working.

I wouldn't like it prefer to control the car myself.

25 minutes ago, F0CUE said:

I wouldn't like it prefer to control the car myself.

I hate Stop/Start and have now found a way to disable mine and keep it from working 99% of the time. If only I could say for sure it will never work again I would post the answer on here for the others that also don't want it.

39 minutes ago, unofix said:

I hate Stop/Start and have now found a way to disable mine and keep it from working 99% of the time. If only I could say for sure it will never work again I would post the answer on here for the others that also don't want it.

Switch it off using forscan. I know the MK3 focus you could do it. 

46 minutes ago, iantt said:

Switch it off using forscan

Would love to switch it off in ForScan but it seems that the option is not there for the Focus Mk4.

If anyone knows of any settings for the Mk4 please share 👍

9 hours ago, John916 said:

Many thanks. Just tried it, and the auto stop/start now works a treat! Thanks again.

John

It won't last my child....it never does!!! 😉

Don’t understand what the issue is with stop/start?

Mine works and is so fast I hardly notice. Great when queues at traffic lights/ road works etc. 

am I missing something here?

43 minutes ago, Andyr55 said:

Don’t understand what the issue is with stop/start?

Mine works and is so fast I hardly notice. Great when queues at traffic lights/ road works etc. 

am I missing something here?

Nope, my Mondeo works every time it should also, that is after having a new battery 12months ago. 

Mine's always worked fine too, had 1 Golf and 3 Focus's with it now (well, technically also another Focus & Leon as well briefly)...  I can only assume people are running the AC on full blast with the heated screens and seats on full while charging their phone streaming a film in 4k...on a half mile trip to the co-op.  

On 7/9/2021 at 9:49 PM, John916 said:

Many thanks. Just tried it, and the auto stop/start now works a treat! Thanks again.

John

if disconnecting the battery really turns off the start stop, I'd be out there today to disconnect the battery and never remember than re-enable method

NOTE YOU WANT THIS BROKEN

Start Stop is VERY bad for the engine, it was only fitted to benefit the manufacturer.
its has two bad for the planet benefits for them and none for us or the vehicle owner. The whole idea is sick and marketed to fools to steal money

1) it increases car sales (the main aim)
2) is drops their pretend CO2 numbers so the don't get fined. Rather than drives them to build ever more efficient and clean engines.
3) destroys the planet with increased manufacturer of cars / engines / starters / batteries / alternators etc. which together produce way more than 1000 times the pollution of burning a bit of fuel. Which after all has the added benefits of keeping the battery charged, the ac / heater working so the driver is able to see and control a car that works correctly... and when working at operating temp is producing less pollution and burning less fuel !!!

START STOP IS A CON JOB

 

 

 

 

All that Botus says sounds reasonable. You would think that starters, batteries, etc. would need replacing more often, but I've never heard that it's actually a problem - my nine year old Mk3 has just had it's first battery change.  Air pollution has been proved to be an issue though, and in a traffic jam it would be nice if everyone's engines were switched off. At Tesco this morning I was surrounded by Tesco vans, all idling for the ten minutes I was collecting my shopping; it doesn't make sense.

But to be honest, I'm a retired engineer, and it just annoys me when something doesn't work!

There are studies that show that the amount of 'extra' polution created when an engine starts is equal to the engine running at idle for 3 minutes. So in order to save the planet the engine needs to be stopped for 3 minutes or more otherwise it is actualy creating more polution. Then there is the massive amount of extra batteries that vehicles are now using, and other related things like alternators.

Each to their own, if you want or like Stop/Start then use it. I just don't think it should be something that is forced by default on those who don't want it, and yes I can hear the crys of those saying well you can always press the button to turn it off every time you start the engine. My answer is well if its that easy to remember why not have it so that you have to press the button to turn it on every time you get in the car?

 

8 minutes ago, unofix said:

There are studies that show that the amount of 'extra' polution created when an engine starts is equal to the engine running at idle for 3 minutes.

I can believe that and is probably the reason that it is disabled if the fuel level is very low in case there is not enough fuel left to successfully start the car.

On 7/10/2021 at 10:15 AM, TomsFocus said:

Mine's always worked fine too, had 1 Golf and 3 Focus's with it now (well, technically also another Focus & Leon as well briefly)...  I can only assume people are running the AC on full blast with the heated screens and seats on full while charging their phone streaming a film in 4k...on a half mile trip to the co-op.  

Lol. Funnily enough this last week weve been doing a detour to work an extra 4 miles each way. So that's 7.5miles to work so in total 15 miles each day and the stop start has sprung into life 🤣

On 7/10/2021 at 10:15 AM, TomsFocus said:

Mine's always worked fine too, had 1 Golf and 3 Focus's with it now (well, technically also another Focus & Leon as well briefly)...  I can only assume people are running the AC on full blast with the heated screens and seats on full while charging their phone streaming a film in 4k...on a half mile trip to the co-op.  

How’d you know my routine? 

its the massive wear and tear on the valve train that is the secret behind the new engine (which is so expensive you might as well bin it and lease a new car)....

BMW and Mercedes deliberately dropped from a duplex chain to a single roller as they introduced start stop - just so it would break and destroy the engines....

and they are dropping like flies

don't think of any car manu as your friend, they are murdering us with designed to fail planet destroying madness

 

so ive been having this issue for about 5 weeks now where my battery would completely die over night , sometimes in a few hours ..., had my car in for a service as the master break cylinder needed to be replaced and i asked if they would check with battery and alternator , turns out its the battery they said and go get a new one as its still under warranty but my question to the ford dealership was .. was the BMS still reading as though the old battery was in and not a new one??? , as when i got the new one installed it was not reset ....they told me that this is not how the computer works and it will automatically reset its self and then i asked did they even check, they wouldnt tell me ... ill be taking the car back to halfords to have the battery sorted . its been a total nightmare .... i have a 2014 focus mk3 start/stop model  , now have Ford just fobbed me off ? or does anyone think that the BMS didnt reset and has caused the battery to be wrongly charged ??

23 minutes ago, littlevixen said:

...i have a 2014 focus mk3 start/stop model  , now have Ford just fobbed me off ? or does anyone think that the BMS didnt reset and has caused the battery to be wrongly charged ??

Why not just reset it yourself using the previously posted method? The only one that cares about your car is you, to everyone else, it's a nuisance, and/or a profit center!

Hi all I have a mk3 Ford focus 2012 titanium with start stop hill assist I have had to replace my battery 2x with 730cc 75amp start stop but nothing works reset my bums starts charging at 14.4 and slowly reduces to what it is now on load at 12.5 would it be my bums system playing up and needs replacing as it’s causing my abs and tyre sensor not to work or charge properly 

1 hour ago, Antony stoner mk3 focus said:

Hi all I have a mk3 Ford focus 2012 titanium with .........

One post on the problem is all that's needed. Multiple posts in different threads just leads to confusion.

Don’t realise I did it twice 

On 7/9/2021 at 9:25 PM, Luke4efc said:

Ignition on,
Sidelights on,
Press rear fog light button 5 times (the bottom one of the two),
Press hazard button 3 times,
Give it a few seconds and the battery light on the instrument cluster should blink a few times.

This worked for me with a 2017 Focus that had the wrong battery installed by a previous owner. I prefer to have the S/S working as per stock setup. Can always turn off using the button provided if required. Great tip 👍