Service Traction. Engine Power reduced. Voltage "A" circuit P0641 code

If anyone has any solutions. I've checked the forums all around and came up with some possible answers, but I need more help.

2009 Chevy cobalt 2.2 L
I was driving along with check engine light for a good while now (my fault admitted) and then suddenly my car felt like it was going to die on me. I pulled over and my dashboard read: Eng Pwr Reduced. And service Traction.

I decided to drive home and when I put it back into drive the transmission shifted into gear delayed and super hard shift which kinda shook the car. So I drove home slowly and parked until it could be looked at.

My mechanic is a great guy and has a computer reader so he hooked it up and it showed several codes. The one my mechanic wants to focus on right now is the P0641 Voltage "A" circuit

I fully trust this guy, he's been the mechanic for my construction company forever. He's super good at diagnosing problems and fixing them so I'm Going with his advice for now and taking this 1 step at a time. But he's doing it for free (or so he thinks---I'll take care of him) so I'm going to be doing some legwork so hopefully we can get this figured out.

If anyone knows anything about the code P0641 Voltage "A" circuit
Or where to find the sensor for that, please I'm all ears.

I will be sure to return with any information I gather
Thank you

Since the P0641 indicates that 5V reference bus A is either higher or lower than expected, I think your guy should focus on the other codes to see which parts are on bus A, measure the bus voltage, then disconnect sensors on that bus one at a time to see if unplugging one of them allows the bus voltage to go back to the 5V specification. Assuming the bus voltage is low and he's able to identify one sensor that seems to be dragging it low, then that sensor is likely bad. Or, if it seems several sensors need to be unplugged to allow the voltage to get within range, then the driver circuit within the ECM may be the culprit.

-Rod