if this is consistent, you may want to consider powering down your device to prevent hardware damage.
this tells us the router has sensed an unusually high chassis temperature. you should verify all cooling system/fans are operational and the 'exhaust' vent(s) are clear and unobstructed.
do a 'show environment all' to see if there are power, heating or grounding problems.
the inlet(s) temp. is measured and is where the air flows into the router.
the outlet(s) temp. is measured and is where the air is forced out of the router. (vents)
