B173d Peugeot Work Work Here

Intermittent or low power supplied to the BSI, often stemming from the Battery Protection Unit (BPGA).

[Key Fob / Transponder] ──(Wireless Signal)──> [Ignition Switch Reader / Slot] │ (Data Packet) ▼ [Engine Management ECU] <──(Validation Request)─── [BSI Computer]

Turn off all electronics, close the doors (do not lock), and remove the key. b173d peugeot work

A story involving code in a Peugeot usually starts with a minor annoyance and ends with a deep dive into the car's "brain," the Built-in Systems Interface (BSI) . This specific fault code refers to an invalid identifier

Fixing a B173D code requires evaluating several electrical and physical failure points: Intermittent or low power supplied to the BSI,

The B173D code is rarely a software issue; it is almost always a physical electrical failure. Common causes include:

This guide is designed for mechanics, diagnostic technicians, or advanced DIYers. It covers the definition, technical explanation, common symptoms, causes, and a step-by-step repair procedure. This specific fault code refers to an invalid

Demystifying Fault Code B173D in Peugeot Vehicles: Symptoms, Causes, and Solutions

: If the code is missing, corrupted, or mismatched, the BSI blocks the Engine Control Unit (ECU).

Reconnect, wait another , then turn on the side lights and ignition without starting for a minute to allow the BSI to re-initialize.