While a faulty key is the most obvious culprit, B173D is often a symptom of wider electrical "confusion" in the Peugeot's complex BSI system.
When B173D is active, you might notice one or more of the following: message on the dashboard. b173d peugeot
On Peugeot and Citroën (PSA Group) vehicles, is defined as: While a faulty key is the most obvious
Sometimes the BSI simply needs a reboot. Glitches in the software can lead to a "Permanent Fault" status for B173D even if the key is perfectly fine. Glitches in the software can lead to a
The simplest cause. If the signal is too weak, the reader near the ignition barrel or in the cabin can't "handshake" with the key.
Turning the key or pressing the Start button does nothing.
It sounds simple, but a fresh CR2032 (or similar) battery fixes a significant percentage of B173D errors. After replacing it, you may need to re-sync the key by putting it in the ignition, turning to position 2, and holding the lock button for 10 seconds.