First thing, check the 12V battery. A bad 12V battery can cause a lot of other faults. The battery may not be bad but if it is really not charging, it will lose enough charge that it will eventually appear to be bad because it can't supply enough current.

The Volt 12V battery doesn't have to supply hundreds of amps like a normal car battery because the main high voltage battery is used to start the gas engine (using one of the electric motors), not the 12V battery. The car does rely on the 12V battery to power up all the modules though , like booting up a computer.

And remember, if replacing the 12V battery, it needs to be an AGM type.

I wonder if the "coolant level sensor fault" is referring to the level sensor for the battery coolant? There are several threads about that. Some people have replaced that sensor / float switch with a resistor because the float switch turned out to be unreliable. This also may be due to dealer-installed float switches instead of factory installed, where the dealer might not have done a good job splicing the wires.

 

Hi Fred_B. Dealer installed battery fluid coolant switches were done on 2011's and early 2012's. Later 2012's and above were factory installed.

An AGM battery holding an 11Volt charge is essentially dead. The OP needs a new AGM battery, imho. I think that a replacement AGM would be the first thing that the OP should do.

 

i cheked batery charging voltage with multimeter, when vechile is started battery voltage is 11 v, from another car with jump emergency cable, chevy vechile started and working without problems

 

That battery needs replacing.

It may not solve your OTHER problems, but an AGM that cannot maintain 12.5 volts for a week is going to cause problems during the startup of all the modules, which will lead to nonsense errors that trigger MIL. 11 volts for AGM is basically completely discharged.