Re: 2009 chevy hybrid, "Service Hybrid System"
 

When key off, the HV battery HV connections are completely isolated from the car... both (+) and (-). Cutting the battery in half via the safety plug does nothing to reset anything.

Removing the safety plug does nothing diagnostically. It only represents risk with no potential reward because MANY do not re-install it correctly. I've encountered incorrectly installed plugs dozens of times because someone read somewhere that they should disconnect it.

The only time the safety plug should be removed is for... safety. Removal of battery or work on the HV system.

Disconnecting the main 12V leads and shorting them is a valid practice.

Re: 2009 chevy hybrid, "Service Hybrid System"
 

I was told that there would still be a connection to the inverter unless the safety plug was removed. I never actually tested it and took his word for it. I just tested it and there definitely is no voltage there when removed from the 12V. battery and the key is off. Ill update the other post to prevent issues.