While many B173D cases can be resolved by a DIY owner with basic tools, certain situations warrant professional assistance:
Locate the BSI unit (typically behind the glovebox or under the dashboard on the driver’s side in left‑hand drive vehicles). Open the BSI casing and visually inspect all fuses on the board. Pay special attention to any 10A fuses that supply power to the key reader or immobilizer. Replace any blown fuse. b173d peugeot work