when the vehicle tries to recognize your mechanical or electronic key.
The B173D code originates from the —essentially the main computer that acts as the central hub for all your car's electrical and security systems. Think of the BSI as a "smart fuse box" that talks to everything: the immobilizer, door locks, lights, windows, wipers, and—most importantly—your car keys. It's responsible for recognizing your key's unique security code and granting the engine permission to start. When the BSI can't correctly identify your key's signal, it logs the B173D error. b173d peugeot work
: It frequently appears alongside other codes like B1808 (engine ECU immobilizer unlocking fault) or B1624 (protection unit relay faults). Common Causes when the vehicle tries to recognize your mechanical
This is surprisingly common. In some cases, the equipment used for the inspection can cause an electrical disturbance or voltage spike, confusing the BSI and triggering this fault code. The fix is often as simple as clearing the code with a diagnostic tool and performing a BSI reset. It's responsible for recognizing your key's unique security
If you were looking for a different "b173d" reference (e.g., engine management, BSI, or ABS), please provide additional context (vehicle model/year or a full fault scan report). Otherwise, the above is the verified Peugeot diagnostic content for B173D.
[Check Battery & Fob] ──> [Perform BSI Reset] ──> [Scan Live Data] ──> [Re-program / Replace] 1. Test the Basics First