I'm having this problem on my 2016 Chevrolet SS. Whenever I start the car, I get the "engine power reduced" message. I just hit the clear button and it goes away. I bet this is the cause. I gotta let my tuner know about this.
Here's a quick cell phone video of exactly what it does. To those that have experienced this, seem familiar?
I wish I still had my hptuners. I had bought it in 2008 and sold it after I sold my G8. I'll be buying it again. This time I'm getting the pro version and plan on keeping it.