9C40 is a fault stored in your BMW's memory (an ISTA fault code, not a standard OBD-II P-code).
Related codes: 9C23 · 9C2D · 9C98 · 9CBA · 9CBB · 9CBD
Decode your BMW's fault memory automatically in Telegram
Free reference for owners. Not affiliated with BMW AG; BMW and CarData are trademarks of BMW AG.