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Saturn Hybrid Shutdown

Car is 2007 Saturn Vue Hybrid, 2.4
From what very little I THINK I understand about this vehicle is that the 36 volt battery pack is sensitive to heat- it has thermistors that shut down the hybrid system if they detect temps that are too high. Then the car just runs off the 12 volt battery until it is drained.
What I need to know is if this scenario were the case, (shut down due to high battery temp) what would be the fix?
Does something need to be reset or replaced?
Thank you in advance for any information.

I believe the Vue Hybrid is the mildest of hybrids in that the system is really just a start/stop version with a generator that is hooked to the engine via a belt.

If the hybrid battery shuts down the car should be smart enough to sense this and deactivate the hybrid system and not run down your 12 volt battery.

However if the battery light on your dash is lit then you will run down your 12 volt battery.

Are there any dash warning lights lit?

After the hybrid system shuts down, the car runs off the 12 volt battery until it is drained- (got 100 miles on it, bringing the car home) The 36 volt starter/generator is part of the ‘hybrid’ system and will not charge the 12 volt battery if hybrid system is shut down.
DTC set was U0120, “lost communication with Starter/Generator Control Module”- Someone suggested in another post that most likely the Control Module would be bad but in reading about this car, I think that other sensors may signal the control module to shut down, i.e. the heat sensors on the 36 volt battery- can’t afford to buy a module if it is not the problem- (can’t afford to buy it if it is)
My thought in asking this question was if some sensor caused the system to shut down, wouldn’t there be some sort of remedy to restoring the function to the system other than part replacement? If the system shut down due to over heated batteries, what happens when they cool down?
I couldn’t find any blown fuses or bad relays.
Basically I’m just fishing around for info to try and piece things together before I have to surrender to a dealer fix and cost. May be something simple, may not.