You should be able to turn the key ON, and within (3) seconds step on the Accellerator Pedal 3 times. Then turn the key OFF, and restart to see if the message reset. Let me know the outcome, and if it does not reset, we'll go from there.
-Rip
Lead Technician
A.S.E Certified Master Technician, AC Delco service training, Ca State Smog License, L1 level