"Wait code"

I own a 2016 Peterbilt 587 with a Cummins Isx engine with 719,000 miles. Almost back to the terminal tonight and noticed that when I accelerated the orange "engine light" and "wait" light glowed stronger. When I backed out of it the lights would dissapear. I kept my speed low and made it to the yard. The lights only come on and glow stronger when I push the accelerator. Any ideas on what this is would be greatly appreciated. Thanks