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B173d Peugeot Work Repack

Understanding Peugeot Fault Code B173D: The Key Identification Error If you’ve hooked up a diagnostic tool like to your Peugeot and seen Fault Code B173D

, your car is likely refusing to start. This code is a common headache for Peugeot and Citroën owners, signaling a breakdown in the communication between your key and the car's security system. What Does B173D Actually Mean? Technically, B173D is defined as a

"Fault in identifying the mechanical/electronic key or hands-free remote control located in the reader" In simpler terms, your car’s Body Systems Interface (BSI) —the "brain" that manages electronics—is saying: "I see a key, but I don't recognize it as the right one" b173d peugeot work

. Because the immobilizer doesn't get the correct "handshake" signal, it prevents the engine from cranking or firing to protect against theft. Common Symptoms Non-starting engine: The car may not even attempt to crank. "Key Not Detected" messages:

Frequent alerts on the dashboard even when the key is in the ignition or reader. Occasional starting: The car might start fine one moment and fail the next. Top Causes and How to Fix Them Clear all fault codes from the BSI

Diagnosis is key here; replacing parts blindly can get expensive quickly. Start with the basics:

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. wait 30 seconds

2. Corroded or Loose Connections at the BPGA Unit

The BPGA unit (also called the Fuse Box Under Bonnet) is a common failure point. Water ingress from a clogged windscreen drain or poor sealing corrodes the relay sockets, causing high resistance and false B173D triggers.

3. BMS Calibration Drift

Sometimes, the B173D is a phantom code. The Battery Management System (integrated into the negative battery terminal sensor) loses synchronization with the relay’s actual state. This happens after a battery replacement without proper coding.

Technical Service Guide: Peugeot Fault Code B173D

6. Post-Repair Procedure

Once the repair is complete:

  1. Clear all fault codes from the BSI.
  2. Cycle the ignition off, wait 30 seconds, and turn ignition on.
  3. Perform a lock/unlock test 5 times using the key fob.
  4. Perform a lock/unlock test using the interior central locking button.
  5. Check for the return of the B173D code. If it does not return, the repair is successful.

The Root Cause: Why Does B173D Happen?

To understand the “work” required, you must know the hardware behind the code. The B173D fault points to one of three failure points: