B173d | Peugeot
Decoding the b173d Peugeot: Symptoms, Causes, and Comprehensive Fix Guide
- If B173D is active → Passenger airbag will be disabled (default safe state in case of OCS fault).
- ➡️ An adult passenger may not be protected in a crash.
- Do not ignore this code or simply turn off the warning with a scanner without repairing.
(Engine management ECU immobiliser reading error), which means the immobiliser is staying locked because it hasn't received the "all clear" from the key reader. Common Culprits Key Fob Battery:
Antenna/Wiring Issues
: The internal antenna that reads the key signal or the wiring connecting it to the BSI may be compromised. b173d peugeot
The wiring harness that connects the glow plug control unit to the four glow plugs sits directly on top of a hot diesel engine. Over time (60,000+ miles), the insulation becomes brittle. The wire leading to Cylinder 4 often rubs against the engine cover or a fuel line, snapping internally. You may see no external damage, but a continuity test will reveal the break. If B173D is active → Passenger airbag will
Note: Always disconnect the vehicle battery before attempting any electrical repairs to avoid short circuits or airbag faults. (Engine management ECU immobiliser reading error)
BSI (Built-in Systems Interface)
In Peugeot and Citroën (PSA Group) vehicles, the acts as the vehicle's "brain" or central gateway. It controls the body electronics (lights, locks, wipers, dashboard) and communicates with the Engine ECU and Transmission ECU.