conditions where the vehicle turns over but refuses to fire. Common Causes
Start with cleaning and checking the connector. Move to replacing the air quality sensor. Only then consider wiring or BSI updates. By following this guide, you should have your automatic climate control working flawlessly within an afternoon, saving yourself a costly trip to the dealership.
: Software glitches or hardware failure within the BSI unit itself. b173d peugeot
When this code is triggered, the vehicle's Built-in Systems Interface (BSI) or immobilizer unit cannot verify the security signal from your key. This usually results in:
in Peugeot vehicles indicates a communication failure between the vehicle’s security system and the key. Specifically, it means the car is struggling to identify either the mechanical/electronic key or the hands-free remote control when it is in the reader. Symptoms and Causes conditions where the vehicle turns over but refuses to fire
: If the battery was disconnected improperly, the BSI may "lose" the coding for the keys. Troubleshooting Steps
B173D cannot be fixed by disconnecting the battery, swapping fuses, or using an SRS reset tool alone. It requires component-level diagnosis and often physical replacement of the seat occupancy sensor mat plus calibration. If you don't have Diagbox, a specialist Peugeot/Citroën diagnostic shop is recommended. Only then consider wiring or BSI updates
: A low battery in the remote can prevent the immobilizer signal from being read correctly .