Engine malfunction/ reduced power

So as the title says my 2010 535i has me in reduced power mode. It started when my serpentine belt broke (total nightmare to change) and I’ve tried disconnecting the battery and all that to clear it, my awd and dsc throws faults at me too but that clears after going full lock left and right. I’ve got full oil and coolant and there’s no audible misfires, anyone got any suggestions?