Electronic system in a vehicle includes crash sensor systems each arranged to sense a crash involving the vehicle and occupant protection systems each including an occupant protection device arranged to protect an occupant in the event of a crash involving the vehicle. The crash sensor system(s) and the occupant protection system(s) are connected to a bus and supplied with power by the bus and communication through the bus. Each occupant protection device is actuated in the event of a crash involving the vehicle as sensed by a crash sensor system. Each occupant protection system may include a power supply for providing power to enable actuation of the occupant protection device, diagnostic circuitry for self-diagnosis, an occupant sensor and a controller for controlling actuation of the occupant protection device based on a signal received from a crash sensor system over the bus, and data from the occupant sensor.