If your start / stop does not work properly on the Focus MK4, this can have different causes.

The first thing you have to know is that various boundary conditions have to be met in order for start / stop to work. Among other things, the outside temperature, engine temperature and battery charge have to be right.

In order for the battery to be charged correctly, the BMS (Battery Management System / Sensor) must properly charge the battery and also return valid values

Hier ist der erste Punkt, den ihr überprüfen solltet, nämlich der BMS

Tip #1

If the exchange did not bring anything or only helped at short notice, it may be that the BMS was not reset / was taught in by the workshop.

Tip #2

If that still doesn’t work – after you’ve given it some time, check

Tip #3

There is a possibility to increase the battery charge level. For everyone who has problems with S / S, feel free to try this.

Meanwhile (beginning of 2023) there is another newer BMS sensor: JX6T-10C679-CC
I’m currently testing this one, so far everything looks very good! video follows