I have purchased new a Citroen C4 Picasso. It is 18 months old an the stop/start system no longer works. It has been back to the dealer on 4 occasions and they have failed to resolve the problem.
The last time I was told by the Service Manager that I should be charging the battery overnight! I asked if there was a trickle charge point on the car but was told there isn't one, and where in the handbook or brochure it tells you to do this, but it doesn't!
It appears that when the battery is not 100% the stop/start will not work - despite me covering 800 miles per week.
Citroen do not seem to have a solution. I have been told that the same problem occurs on the C3 and the only way to cure it is to turnoff the AC and lights, but this does not work with my vehicle.