After turning off keyfree entry on my 2019 MK4 Ford Focus it has failed to turn back on. Before this it worked flawlessly on all the doors and trunk.

In the menu, when pressing the "Keyfree Option", it just quickly flashes and stays checked - without actually working. All the other options work as intended and stays checked/unchecked when pressed.

I have tried BMS reset - I have not tried OBD/Forscan. I have a movie explaining the flashing option, but I cannot upload it.

 

10 minutes ago, FocusedAF said:

I have tried BMS reset

Oh God why ??????????????????????

Only reset the BMS when a new battery is installed.

The keyless door system has been disabled by the vehicle to save power because the battery State Of Charge is low. You need to use a smart charger and recharge the battery for at least 12 hours. Then the vehicle will need to go through at least one start cycle and the doors locked with the fob before the keyless system will be fully reinstated. It's normal for the system to be suspended if the SOC becomes low.

11 minutes ago, unofix said:

Oh God why ??????????????????????

Only reset the BMS when a new battery is installed.

The keyless door system has been disabled by the vehicle to save power because the battery State Of Charge is low. You need to use a smart charger and recharge the battery for at least 12 hours. Then the vehicle will need to go through at least one start cycle and the doors locked with the fob before the keyless system will be fully reinstated. It's normal for the system to be suspended if the SOC becomes low.

It was suggested to me in another forum as it had worked for other people. What harm can a BMS reset do? This made my start/stop work again, it had never worked before this.

I have taken 4h trips with the car, wouldn't this be enough to charge the battery?

Just now, FocusedAF said:

What harm can a BMS reset do?

You have now reset the battery age. The charging system adjusts its characteristics according to the age of the battery to ensure optimum use and life of the battery.

Driving your car will not recharge the battery like it would on older vehicles. It would take a none stop trip of at least 100 miles and with out the use of things that take a lot of power for the alternator to stand a chance of recharging the battery to 80% which is the maximum it will ever recharge the battery to.

When using a smart battery charger, ensure that the negative lead is connected to the chassis earth point and not the battery terminal, so that the BMS will know that the battery has been recharged.

2 minutes ago, unofix said:

You have now reset the battery age. The charging system adjusts its characteristics according to the age of the battery to ensure optimum use and life of the battery.

Driving your car will not recharge the battery like it would on older vehicles. It would take a none stop trip of at least 100 miles and with out the use of things that take a lot of power for the alternator to stand a chance of recharging the battery to 80% which is the maximum it will ever recharge the battery to.

When using a smart battery charger, ensure that the negative lead is connected to the chassis earth point and not the battery terminal, so that the BMS will know that the battery has been recharged.

Appreciate the quick response, I will look in to that. You make it sound like a BMS reset is the end of the world, could I have damaged something when doing this? Almost every post regarding failed stop/start suggest this method, I'm not saying it's the correct way of solving the problem though.

5 minutes ago, FocusedAF said:

I'm not saying it's the correct way of solving the problem though.

The problems of Stop/Start is a whole other subject of which there are over 250 threads on this forum. Reseting the BMS sometimes fools the system in to thinking the battery is fully charged when it's not. On occasions the infamous S/S will work for awhile but once the BMS has chance to recalculate the true SOC it will once again disable the system.

2 minutes ago, unofix said:

The problems of Stop/Start is a whole other subject of which there are over 250 threads on this forum. Reseting the BMS sometimes fools the system in to thinking the battery is fully charged when it's not. On occasions the infamous S/S will work for awhile but once the BMS has chance to recalculate the true SOC it will once again disable the system.

As I understand it, the car will now charge the battery slower than before the reset - because it thinks the battery is new? This should be fine right?

I did the BMS reset in March and SS still works, unfortunately it did nothing for the keyfree entry, which is a shame because I can totally do without SS 😄

Appreciate the help!

1 minute ago, FocusedAF said:

As I understand it, the car will now charge the battery slower than before the reset - because it thinks the battery is new? This should be fine right?

The mysteries of the Ford smart charge system is shall we say a "mystery" 🤣 You should be fine and the BMS will have recalculated the true SOC by now.

There is a simple little device that you can wire in that automatically disables S/S every time you start the car. I sell them here in the UK, but I see you are probably in Europe so you can get them from https://www.formod.eu/

On 5/7/2024 at 9:42 PM, unofix said:

The mysteries of the Ford smart charge system is shall we say a "mystery" 🤣 You should be fine and the BMS will have recalculated the true SOC by now.

There is a simple little device that you can wire in that automatically disables S/S every time you start the car. I sell them here in the UK, but I see you are probably in Europe so you can get them from https://www.formod.eu/

Got it fixed under warranty, it wasn't battery related, they had to update the software because for some reason the key information had been lost. Got a very vague explanation unfortunately.