Denali xl 04'

Need comment on Denali xl '04, Yesterday my Denali acting up the messaged shown "REDUCED ENGINE POWER", and the same time "STABILITY SYS DISBLE" also flashing. I did try switching T/C but didn't works. In the mean time truck was absolute no TORQUE at all. It is only able to drive no more than 25-40 m/hr maximum. Then I drove to the dealer and turn the engine off for 5 min. and then when I trying to shows to technician. The truck was operation normally. Right now truck still in the dealer to fine out what was the problem. Anyone has similar problem.