96 grand am coolant sensor

on my 96 gr am gt, 3100...the check engine light came on so i ran computer scan. scan showed coolant temp sensor overcharging. what can cause this. tx budman

Just a thought...How many miles on the coolant that is in the car? Sometimes old or weak coolant will play havoc, I have see cars that have a coolant level sensor show "low coolant" but the systen was full it turned out to be old coolant and a dirty sensor.
I don't know if this is your case but if the coolant is old it surely will not hurt to change it.