Seem to be accurate enough for black and white measurements. As in, when it says 'Charged' - Start / Stop works... When it says 'Partially Charged' or 'Critical' - it doesn't
2019 Glc coupe 350d was 2017 e350 c207 .. +65 ford kuga 2.0 cdi zetec awd..
Should be able to use steering wheel buttons , press hang up phone and hold it down then immediately press ok. Takes you into a service menu. My e350 also displays battery condition on the comand screen in vehicle data screen.