Many people see the B173D code and immediately assume the worst, like a failed security module. In reality, the symptoms are often much simpler and more mechanical. A B173D fault typically presents itself in one of these ways:
Start the engine. Monitor live data: pre-heat relay status should show “Activated” for 1–3 seconds on a cold start. Drive the vehicle for 10 miles. Re-scan – B173D should be gone.
Internal damage to the key fob's PCB from drops, water exposure, or magnetic fields. b173d peugeot work
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Every keyless Peugeot features an emergency transponder slot or a designated spot on the steering column where the key can be held. Placed here, the vehicle reads the chip using passive electromagnetic induction. If the car starts using this method, your issue lies strictly within the remote's battery or the vehicle's long-range antenna network. Step 2: Replace the Key Fob Battery Many people see the B173D code and immediately
Parking near high-voltage power lines, telecommunication towers, or utilizing aftermarket electronics (such as cheap dashcams or USB chargers plug into the cigarette lighter) can disrupt the 433 MHz frequency used by Peugeot smart keys. 4. BSI Software Corruption
Now that you understand the problem, let’s fix it. Start with the easiest, most common checks and work your way through the list. Monitor live data: pre-heat relay status should show
: If the code is missing, corrupted, or mismatched, the BSI blocks the Engine Control Unit (ECU).
The key has lost pairing with the car's BSI.