Fiesta speedomoter and stalling

[Vic56]

Hi there,
I have a 2007 WQ LX 5 door hatch that has the speedometer suddenly drop to zero. Sometimes, but not always, after this happens a few kilometers later the car just stops. As soon as I restart it all goes back to normal and it can go a week without doing it again or it might do later the same day. I had a Auto Lan Diagnostics done which only said a problem with the dash control panel but nothing specific. Anyone else had this problem or have any idea what may be causing the problem? TIA😊