the light is on and the level registers low until the car warms up then the light goes off...
low coolant level light is coming on. once the car warms up the light goes off.? on 2001 Volvo S80
check your coolant when car is cold if it is ok it might be a bad level sensor
agree with good guy. if the coolant is low have system pressure tested to determine poss leak
you are low in coolant...top it off and if this repeats...find a shop to help you find that leak