I have a similar problem with stop start system.. I had it into the local nissan dealer and the diagnostic check flagged up the brake fluid was low but it is fully topped up.
They can't find any other faults

Hi all. Looking for some advice, When I start the car I get a message saying stop start system fault. The auto hold doesn't work. There is some lights on the dash that shouldn't be. I had a so called breakdown guy out last night he told me that the rear brakes were in serious need of replacing. And ...

Hi thanks for your reply. The battery was replaced by the RAC 2 years ago

I am having the same trouble with my stop/start. On my J11 2017
I am getting a few warning lights on the dash, the stopstart won't work and the handbrake has to be applied manually.
Is this safe to drive like this...
Any help appreciated.