I have a Nissan x-trail 2015, which all of a sudden doesn’t start was told is the battery, changed it and then a auto system start stop message appears and disappears constantly flashing on and off . then it starts at random and drives normally with no issue. I believe it’s an electrical issue but not sure what mechanical issue, this can go on for days at a time or as little as in minutes and then goes to normal and starts again. I have taken it to four different mechanics none have found an issue with the car even after a diagnostic test. The car was reset back to factory settings and started working for a month with no problems now the issue is back.