I had a nasty shock recently, My 2015 Ford Fiesta failed to start several times, I took it to the local garage but they could not help, so I took it to a Ford Main Dealer, (£90 per hour).  They said the instrument cluster needed software updates, which I knew nothing about, there is nothing in the manual about this, so I sent a stiff letter to head office in UK, with questions. Why are these things not explained in the owner's manual?  Why are these software updates not done in the annual service?  The PCM is the Power Control Module, or onboard computer.  Why can't owners do the updates at home from their own computer?

There are other things not in the manual that should be, such as battery replacement.  If you disconnect the battery, certain engine components might lose important data, so DON'T,  unless you know what you are doing.

I'll keep you posted.

yes keep us posted. I'm interested in the final outcome, it sounds a bit odd to me and needs some further explanation. if it's down to the software in the instrument cluster why has it not always had this same problem. 

Very odd that you cannot disconnect your battery to say put a new one on....

is it a software update to the instrument cluster module or the Powertrain control module ( PCM )? since they are two completely different modules , and as far as I know the instrument cluster module has nothing to do with troubles in starting the engine , and also about the PCM , PCM software updates are meant to improve performance, eliminate bugs in the software that could have caused issues before, for example hard shifts in an automatic transmission, or performance related issues regarding the engine, so a software update to the PCM also has nothing to do with the your problem of failing to start the engine, the only thing I can understand is that if your issue is PCM related in the first place it would be that this module has failed completely !! , they should have cleared the issue for you much more so we can understand what is happening, please keep us updated 🙂 

Reading between the lines , his post sounds like his battery is losing its charge therefore having starting problems. Ford may have diagnosed the instrument cluster as a possible source of current draw therefore a software update may cure the problem. Modules can randomly have current draw issues at any time for some unknown reason. The software update may fix this bug . 

This is just an educated guess without all the facts.