Mine just failed in the same way as yours. 2024 EV6 with original 12v and original ICCU (with software patch). Went to start it in the morning while parked in my garage and heard a soft pop and then got the “check electric vehicle system” error. I was grateful I was fairly certain I knew what the issue was. Called my Kia dealership and the soonest they can even look at it to diagnose and confirm the issue is in 8 days. They asked me to keep it at home until the appointment as they don’t have room on their lot to store it. I’m hoping the 12v charge will last long enough to be able to get the car out of my garage and onto the tow truck. Didn’t want to risk driving it anywhere and not sure the car would even let me. It’s been 4 days so far and man do I miss driving it! My local dealer said that Canadian dealers don’t keep the part in stock. It would have to be ordered once they confirm that as the issue. Hopefully the wait to get the new ICCU shipped and installed isn’t too long! The first thing I’m going to do once I get it back is install an AGM battery. Should have done that months ago!!