stop start function not working

[steveq]

I doubt that fuel consumption with Start/Stop will be noticeably different on any engine, Diesel or petrol (unless you're regularly stuck in traffic jams and for long). Modern engines use only a very smal amount of fuel when idling anyway.

Fuel consumption reduction is one benefit of Stop/Start for the car owner. Of equal importance is the benefit of lower emissions. S/S really only operates in urban areas at traffic lights or traffic jams. These are generally areas of poor air quality so anything that can be done to reduce pollution has to be good.