I'm not an attorney, but given the repeated stories and similarities in our experiences, I'd like to see what the pulse may be for some sort of class action.
I specifically shopped for a GM Certified car in Nov. 2021 because I believed the warranty would be important. Three months later, the BECM was diagnosed as bad. The warranty covers repairs, but I've been waiting more than a month with no ETA on a part. Some online suppliers seem to have the part in stock, but the dealer says they can't use a part that's purchased elsewhere. The warranty provides courtesy transportation, but the dealer claims there are no loaners. They won't return my calls. I complained to GM, and they said they would look into it, but I haven't heard anything back yet.
The 2018 warranty explicitly states: "A part not being available within 10 days or a repair not being completed within 30 days constitutes a significant inconvenience."
If anyone else who has not received adequate service when their battery energy control module failed would be interested in looking into a class action, please PM me or email me (zimmerdale at yahoo dot com) with your name, phone number and/or email, your state, year of your Volt, and a brief overview of your experience, I'll try to compile a summary for circulation to see whether anything can come of this.