I recently purchased a brand new 2020 bolt and a similar issue happened to me. I was driving to work last week when the service car symbol appeared. I pulled over and got on star to pull the code - P16EA. The car went into reduced propulsion power mode after I continued driving to work. I was really bummed out because the car is only a couple of weeks old with ~2000 miles and already throwing a code. I took my bolt into the dealership and after 1 week of ‘diagnosis’ they told me they were instructed by Chevrolet to reset the code and that I could pick up my car - they said that if the issue comes up again, the HPCM would have to be replaced. I got to the dealership, turned on the car, and the service car symbol appeared immediately....
All this to say, I’m really frustrated and I suspect some greater issue to be causing all of this. Maybe a faulty battery? I will be sure to update you with the outcome of my broken bolt.. I’m wishing I dished out the extra money for a model 3 at this point.