The fact that the PATS light does not illuminate at all indicates that the ECU is not receiving any ignition feed.

I had this on my Fiesta 1.25 with the Siemens ECU. Started the car up with a low battery level, it ran and moved about 1 foot then stalled. The alternator had spiked (similar to your problem) and shorted the ECU internals which had blown the ignition fuse in the engine bay. Double-check your fuses in the engine bay.