See the PDFs at charging port will not accept charging cable.Just had the J1772 locked out for the fourth time, disconnecting the 12VDC negative cable did the trick, thanks very much for that idea ! The first three times I took it to the dealer, they downloaded a software patch and told me it was not a permanent fix and they claimed the problem was only with 2019 Bolts which had a battery replacement. I keep asking the dealer, but no fix from GM yet. Spent an hour on the phone with GM today, finally reached someone who would generate a customer complaint, I should hear back within a week, will report back if anything helpful occurs.
Besides receiving a VERY nice check in exchange for my '19, I guess I'm happy that my Bolt got bought back. Mine had DC FCi inlet so having to disconnect the 12 volt as a workaround for this prob would be pretty annoying. I never had my pack replaced and never had this problem in the 3 years I owned '19 Bolt.
And, there are still Bolt bans at some places here in CA.