66 plate xc60 cuts out and won't re start
 

Hi everyone, searching for an answer.

We have a 66 plate xc60 2.4 D4 AWD. It's got 18,000 miles on it and we like it alot. Except, recently it has begun to cut out for no reason. It's been into the dealer and they can find no faults and have completed a software upgrade.

To give a little more detail, when you pull up to a junction and apply the break the start stop kicks in. Most of the time this all work's but on 3 occasions the car has shut off entirely and will not start. Twice this has left my wife in dangerous positions.

Any ideas would be gratefully received.

Thanks in advance.