Engine shuts down when driving.

[thoco1]

Hi. I need advice please for the following problem on my 2011 MC Mondeo diesel TDCI automatic.
On four occasions the engine has shut down while driving. On each occasion the ENGINE MALFUNCTION display came on. The first time I opened the MESSAGE screen and it told me I had a coolant problem. This was repaired and the car travelled for a further 1000ks (approx) without any problems. The next three occasions, again after travelling about 1000ks, the engine shut down, the ENGINE MALFUNCTION display came on and when I switched to the message screen it told me there were NO MESSAGES. The engine started first time on each occasion and the ENGINE MALFUNCTION did not display. I was also able to give the engine some revs without any problem. But as soon as I moved the gear lever from the PARK position the engine stopped, the ENGINE MALFUNCTION display came on and again there were no messages. On each occasion the roadside patrol person checked on the diagnostic tool but did not identify any faults. On each occasion I arrange to be towed to a different workshop, they each did their diagnosis but could find no fault codes. So far I have had the air conditioning condenser replaced, the engine fan replaced and the transmission serviced all to no avail. The car is currently in a workshop and the mechanic takes it out regularly to see if he can replicate the problem but to no avail.
I wonder if anyone else has experience this problem. I note that there are posts on engine stalls but none that appear to be exactly the same as mine.
Any help would be greatly appreciated.