Hi, iv just purchased a 2012 ford focus zetec ecoboost, lovely car to drive etc, one issue is the start stop , was working I disabled it, then enabled it  again, but it's doesn't seem to be working, anyone any suggestions on what to do to get the start stop working again, thanks in advance 

The battery needs testing to check the state of charge, start stop will only work when it's over 70%

Thank u, I will get it tested 

I only got the car last Friday, and the start sing, until I disabled it, then tryed to enable it again and it hasn't worked since

The amazing thing is that the start/stop worked at all - it usually doesn't with anyone else that has it 🤣

11 minutes ago, StephenFord said:

The amazing thing is that the start/stop worked at all - it usually doesn't with anyone else that has it 🤣

Yeah guy I know, says his works sometimes, is this a manufacturing fault or as the other guy commented is it down to the battery being less than 70%,i have only had car from last Friday

1 hour ago, StephenFord said:

The amazing thing is that the start/stop worked at all - it usually doesn't with anyone else that has it 🤣

Car swap with unofix….? Haha 

There's quite a long list of conditions that need to be satisfied for it to work. Ambient temp in a certain range, battery charge, load on the battery (eg if you've got headlights, radio and a/c on it may not work as there's a large draw on the battery) plus a few others.

You can do a battery system reset which sometimes gets it working again. Power the car on but don't start the engine. Press the rear fog light button five times followed by the hazard button three times. Wait for a bit (around five or 10 seconds from memory) and you should see the battery light on the dash flash a few times. All done.

This happened to me, I charged the battery (it was very low) and then reset the battery monitoring system 

 

10 minutes ago, nibnob21 said:

You can do a battery system reset which sometimes gets it working again. Power the car on but don't start the engine. Press the rear fog light button five times followed by the hazard button three times. Wait for a bit (around five or 10 seconds from memory) and you should see the battery light on the dash flash a few times. All done.

Why would an ordinary 'Joe' need to go through such an awful palava just to get their car to work as supposed to?? It's a dreadful design, and inherently unnecessary! And as for being, 'green', there are 1000s of owners replacing perfectly good batteries in an attempt to get the darn thing to work. If it doesn't work in your car, think yourself lucky and worry about something important...

11 hours ago, StephenFord said:

The amazing thing is that the start/stop worked at all - it usually doesn't with anyone else that has it 🤣

A good friend had a brand new Fiesta MK7.5, when it came out that is! that had the start/stop fitted and he used to brag about it, three months into owning the car his car was back with Ford, new starter motor fitted, it kept jamming, a month on and it was back in with Ford, car nearly died a death! All the cables from the starter to the battery had melted, blowing fuses and Ford had to renew the starter motor - all cables - new battery 👎

Ford explained to my friend that it's just teething troubles and several has come back with similar faults 

Ford using their customers as beta testers again.

9 hours ago, nibnob21 said:

There's quite a long list of conditions that need to be satisfied for it to work. Ambient temp in a certain range, battery charge, load on the battery (eg if you've got headlights, radio and a/c on it may not work as there's a large draw on the battery) plus a few others.

You can do a battery system reset which sometimes gets it working again. Power the car on but don't start the engine. Press the rear fog light button five times followed by the hazard button three times. Wait for a bit (around five or 10 seconds from memory) and you should see the battery light on the dash flash a few times. All done.

I did the battery reset a few days ago and it didn't seem to do anything,  I went to work today in car and when driving home it started working again, I'm wondering since iturned the start stop off, then  turned it on, I'm done around 50/100miles, does it come back on after being turned off, after a number of Miles has been reached? 

2 minutes ago, Graeme stitt said:

... does it come back on after being turned off, after a number of Miles has been reached? 

You'll notice that today starts with the letter, 'W', and this is month no.7. If you were traveling at more than 18MPH prior to stopping, and heading into the wind, on a 'w7' day, there's a more than 27% chance of start/stop working...

I know some peoples s/s works all the time and other like mine never works no matter how many miles I do, but have just seen a YouTube video (in German) where he says his car was fitted with the wrong BMS sensor at the factory which causes all the problems.
 

 

11 minutes ago, Mark-UK said:

I know some peoples s/s works all the time and other like mine never works no matter how many miles I do, but have just seen a YouTube video (in German) where he says his car was fitted with the wrong BMS sensor at the factory which causes all the problems.

 

What an interesting video! Thank goodness for YouTube subtitles. I wonder how many posters here have the issue of an incorrect BMS fitted?

Ford dealers should be aware of this 😂😂😂 I've changed a few 🙄

3 minutes ago, MasterTechTip said:

Ford dealers should be aware of this 😂😂😂 I've changed a few 🙄

Has the original BMS been faulty, or have you just been eagle eyed enough to see that an incorrect one has been fitted?

When a diagnostic session is run which is a must for Ford Warranty otherwise the dealerships do not get paid, it should come up as a "test" to check the partnumbers of the BMS sensor. That BC variant is known problematic sensor. 

21 minutes ago, MasterTechTip said:

Ford dealers should be aware of this 😂😂😂 I've changed a few 🙄

It would be interesting to know what problems the old sensor gave, i.e. was it not allowing the battery to charge quickly enough or just not recording the charge correctly.

Sorry to bug you but do you know if the new sensor needs to be programmed into the system. Presumably the State of Charge is stored in the BCM. I'm not bothered about Start Stop but if it allowed the battery to be charged quicker instead of the pulsed 0 to 2 or 3 Amps that it often charges on when in conventional mode then I would buy one myself.

I'm not 100% sure of the fault in the sensor but I think it gave conflicting messages to the BCM so it always thought it needed charging. At the end of the day all it sends is reference voltage back to the module so if it's even out by 0.1 of a volt it could mess the whole system up. 

A new BMS would just need the reset doing either through diag equipment or the in car way.

As far as I'm aware the sensor itself isn't in command of how quickly the battery gets charged it only gives the BCM something to reference in regards to the charge rate. 

Well thats another full page on the fun of Start/Stop 🤣

The good news is mine never works now since I fitted a 10 ohm resistor across the back of the switch - a very good result 👍