If you haven't resolved it yet, I got the same message (not sure of the exact numbers or code though) while trying to power up, if the S90 or surrounding room temperature was too cold, like brought in from a cold truck or set up in a very cool environment (I live in Canada and have been forced to set up in winter for sound checks in very cold halls and arenas).

In many cases at first I would just get a blank display, then a few minutes later upon retrying I would get the error message. At that point I just let it sit powered on with that message, and like a car in winter I'd just let the unit warm up for 10 minutes or so, then after powering off and on it usually worked fine.