I bought this car a few months ago and have been very happy with its performance and good MPG - approx 54mpg overall.  Can anyone advise me whether this model should auto stop-start for example at traffic lights?   Mine doesn't.  thanks in advance for any suggestions.

Update:  I found the setting to switch autostop on and off and it is set to ON but still doesn't work !

Stop start failure can be due to numerous things like low eng temp etc but the main popular reason reason for it not working is that the battery is not charged up enough, car left standing for days/low use, or even the battery itself is on the way out.

Hi Trevor,  thanks for your reply.  It hasn't worked after a 350mile motorway run which should have had the battery at full charge, so I don't think it can be one of your "popular" reasons. 

I'd put money on it being the battery too. The smart charging system in modern vehicles isn't as simple as it used to be, and depending on driving conditions and throttle use even a single long motorway run might not be enough to get the battery above the minimum charge required for the stop/start to work. Regular use seems to help a bit, but it might be the battery itself needs replacing. I had similar issues and a new battery sorted the problem. 

Hi. New to this forum. we have a 2015 focus trend 2.0 turbo diesel. our auto stop hasn't worked for awhile and now we are having intermittent cluster faults. could this be a battery issue as well. cheers in advance from New Zealand

On 2/6/2023 at 6:09 AM, Wayne Webb said:

our auto stop hasn't worked for awhile

You're a very lucky guy, I had to install a little gadget on my car to keep it turned off.

If you are getting random electrical problems then start by measuring the voltage at the battery terminals about 1 hour after parking up. Use a multimeter and be accurate when taking the reading.

See the table below for the State Of Charge (SOC) of your battery. If it is below 70% then put the battery on charge for at least 12 hours. Make sure the charger negative lead is connected to the vehicle chassis earth point and NOT to the negative battery terminal.

I have this problem intermittently and the battery has been proven good by Ford.  What I do:

Battery Monitor Reset:

1. Turn power on, but not the engine

2.  Flash headlights 5 times

3.  Press brake pedal 3 times.

4.  Battery should flash 3 times, this indicates it has reset.

Leave it for 20 minutes, then go for a drive, you should have teh S/S working now.  I tend to have to do this maybe 3 times a year.

 

The BMS should only ever be reset when a new battery is installed.

Each time you reset the BMS it clears the 'Days in Service' counter for the battery, and the current stored State Of Charge (SOC).

It is not dealing with the actual issue which is the battery simply needs charged. All it's doing is fooling the BMS in to initially thinking that a new fully charged battery has been installed. After a time the BMS will eventually work out the true SOC and so the status quo will have returned.

ALL makes and models of modern cars suffer the issue of the battery SOC reducing over time, due to the smart charging systems used (actually not very smart). Depending on the vehicle use, and many other factors the rate at which the SOC decreases with time varies from as little as 5 weeks to as much as 5 months. One thing is for sure, and that is it will decrease.

Hi again - I checked my battery against the table shown by Unofix.  The car had stood overnight in about 5C temperature after a short run yesterday of about 10 miles.  Battery voltage was 12.36 which I would think equates to about 75% SOC.   Is that low enough for auto stop-start to not work?  If that is the case then I will live with it as I don't se the need to spend anything on a battery that is performing OK.

The dreaded S/S requires nearly 114 different things to be 'Just Right' before it will operate. The state of the battery is just one of the items that is checked for.

To answer the question on the State Of Charge, it's not an exact science but 70% +/- is the cut off point.

Battery temperature, both hot and cold play a major part in the vehicles consideration as to whether S/S will operate or not. The key thing to always remember is that the Start/Stop system is designed to only operate when the vehicle considers it appropriate, and not when the driver thinks it should.

thanks unofix  - I guess the car is smarter than me!

16 hours ago, unofix said:

You very lucky guy, I had to install a little gadget on my car to keep it turned off.

If you are getting random electrical problems then start by measuring the voltage at the battery terminals about 1 hour after parking up. Use a multimeter and be accurate when taking the reading.

See the table below for the State Of Charge (SOC) of your battery. If it is below 70% then put the battery on charge for at least 12 hours. Make sure the charger negative lead is connected to the vehicle chassis earth point and NOT to the negative battery terminal.

So. Went to collect car this morning,  asked auto tech to test battery voltage and load test. Voltage test was 12.08v, load test was ok, volt test again after load test returned 12.18 volts. So we are getting a new battery fitted tomorrow, $850.00 NZ dollars fitted !! 😣😢 Will let you know if issues have been sorted. Thanks for the information and help. Cheers from New Zealand 

I recall a Ford ‘master technician’ telling me the S/S is a very complex set of things that, like Unofix said, have to be just right.  
 

I know the bms reset is for a new battery, however I’ve had issues where the s/s doesn’t work, nor the heated screen.   I assumed at the time it was the battery, I’d already had one replaced under warranty due to a recall in the cars first year, however Ford dealer checked the battery over and proclaimed it was still good.  
 

I’ve only ever had to reset it twice fortunately.   It’s behaved, more or less, since then.   

Well. New battery fitted, auto stop now working as it should, yay. Will be a waiting game to see if the intermittent cluster fault has also sorted itself out.