SYNC doesn't like my wife's phone anymore

[Martyboy78]

Morning.  We have a 2014 Ford Grand C-Max.  I have an iPhone 8, my wife has an iPhone XR.  The car has a basic version of SYNC, I think it's 1.1.

My wife travels a lot for work and uses the SYNC for phone calls a lot but a couple of weeks ago the car simply stopped recognising her phone.  My phone works fine - I am able to delete my phone, then reconnect it and then redownload my phonebook to the car.  I can do that multiple times, no problem.  But the car won't even let me delete my wife's phone - it will say it's connected for about 5 seconds and then tell me her phone is disconnected again.  It won't download the phonebook from her phone in the few seconds it thinks they are paired.

I have scoured the internet and tried various fixes (all listed below), none of which have worked.  Does anyone have any other ideas before I contact a dealer please?

Essentially the car is treating my wife's phone as a hostage - it won't let it leave and it won't let it do anything either.  I can't work out if it's the car (in which case why don't I have a problems with my phone?) or my wife's phone that's causing the issue.  As I said her phone worked perfectly ok for months.  We are both running the same ios software on our phones.

Things I have tried:

On the car:

Resetting SYNC and restoring defaults / master reset

Turning bluetooth off and on again

Deleting my phone's wife (won't let me)

Removing the fuse from the passenger compartment (I've done this for 30 seconds, 1 minute, 2 minutes and 3 minutes).  Didn't work.  Incidentally, the manual of my car doesn't list a "SYNC" fuse or a bluetooth fuse so I removed the radio/audio fuse.

On the phone:

Forgetting the device and reconnecting it

Switching bluetooth off and on again

Changing the name of the phone

Turning the phone off and again

Turning airplane mode off and again

Resetting the network settings

Updating the software settings

[Nismex]

I've had this on mine in the past. Daft question I know but if I turned the car off, removed the radio/sync fuse, re inserted it (1, 3 or 5 mintues etc) then turned back on, it didn't cause the system to reset/re initialise for me.

I had to :

Engine off > remove sync/bt fuse > turn engine on > turn engine off > insert fuse > turn back on 

only then does it seemingly re initialise for me.

There is also the issue that I believe iOS 13 through 13.1.1 has bluetooth bugs, and Apple release 13.1.2 iirc to address some bluetooth car issues.

[Martyboy78]

3 minutes ago, Nismex said:

I've had this on mine in the past. Daft question I know but if I turned the car off, removed the radio/sync fuse, re inserted it (1, 3 or 5 mintues etc) then turned back on, it didn't cause the system to reset/re initialise for me.

I had to :

Engine off > remove sync/bt fuse > turn engine on > turn engine off > insert fuse > turn back on 

only then does it seemingly re initialise for me.

There is also the issue that I believe iOS 13 through 13.1.1 has bluetooth bugs, and Apple release 13.1.2 iirc to address some bluetooth car issues.

Thanks Nismex - I'll try that and let you know!