Vehicle was parked in garage overnight in our house. At approximately 630AM, carbon monoxide detector alarmed indicating high CO levels inside the house. Source likely appeared to the vehicle- distinct odor of burned electrical wiring/insulation; vehicle felt warm to the touch. Vehicle was dead and would not start. Mazda app indicated critical warnings for ACTIVESENSE, hydrid battery, hydrid system malfunction, high voltage battery depletion, and charging system malfunction starting abruptly at 0210 hours and terminating at 0340 hours. Vehicle had simply been parked in garage and was not plugged in or charging. Last use of vehicle~930PM the night prior. There have been no prior warnings or indications of problems, vehicle has~1k mileage. Vehicle was purchased 7/5/23 and event occurred 7/30/23. Vehicle was towed and is in dealership currently. Mazada USA has been notified by us. Main concerns: 1. Spontaneous carbon monoxide emission of a brand new hybrid EV vehicle model that was parked in a residential home; not plugged in or charging. House full of adults and children overnight. 2. Possible electrical issue with EV/hybrid system leading to spontaneous incomplete combustion of some electrical/battery component.

- Mclean, VA, USA