Red triangle with ! and "check system" on the multi display is TPMS (tire pressure sensors).... you can't read the check system since it's japanese I guess.
Low tire pressure (you said you checked this)
You switched to the second set of sensors by accident (done with the multi-switch that looks like <o> to left of steering wheel).... since I presume you don't HAVE a second set it's thinking it's getting no signal.
Defective TPMS sensor (not likely, but possible I suppose)