Surface Pro 4 type cover suddenly not working.

Well last night while watching youtube in bed till about 1:30am seen the power saving came on and for whatever reason again keyboard stop functioning so took keyboard off put it back on charger tried a few restarts hard and soft to no avail enabled the updates again and went to bed and this morning tilt was back working so plugged in the cover and bing bang boom back up and running again. Very sporadic and random but maybe power saving measure seeing as back now.

If it helps I also purposely installed wrong drivers on the 3 hid keyboards in keyboards and the same with the mouse one. Forgot I did that as wanted to rule out conflicts, but they still same as I left them.

You could try disconnecting keyboard

Uninstalling all available windows updates that are removable

Open device manager

Uninstall (tick where available) all firmware's bar surface touch

Update the hid 3 keyboard drivers and 1 mouse driver to something wrong

Uninstall the surface integration service device from under the system devices tab

And power button and volume up for the max length (keep it held in even in uefi) let go and power on when no more restarts happen

Goto windows update take whatever it has available

Then leave it plugged into power go do something then come back lift it and tilt if the orientation comes back plug keyboard in if it doesn't rotate same again, leave it a while just don't plug the keyboard in till the sensors get a touch of the god juice cause till that array of sensors comes back keyboard won't work (from the randomness of my experience anyway) ✌

See, it's stories like yours that keep me fiddling with this thing. I've had my Type Cover spontaneously start working twice in the last couple of months, for no reason that I've been able to discern. And then it stops working after a shutdown. None of the myriad suggested fixes have been effective. 

To quote Chief Dan George in Little Big Man: "Sometimes the magic works, and sometimes it doesn't." Looks like the latter is more common on my machine.

Weird Last night I did the usual uninstall of firmware's and surface integration device and today I've just got home to a fully working sp4 I have no idea whats going on only updates were defender definitions. Checked GPS orientation and type cover close sensor all working splendidly also keyboard touch pad and keyboard lights are all back. I'm on 1903 which got a quality update yesterday (maybe cause I uninstalled all updates that I could) crazy times just hope it sticks, I've turned updates off for next 7 days and hopefully nothing changes and I have my £2k surface back again fingers crossed

For now, physically disconnect the keyboard from the surface, wait 30secs, and then connect again, the keyboard should start working until next time...