While this code can appear in any modern Peugeot, it is most frequently reported in:
: A weak battery in the remote can prevent the car from "hearing" the electronic handshake it needs to start.
: Communication issues between the key reader and the BSI can prevent valid identification.
associated with the vehicle's immobilizer and key recognition system Overview of Fault Code B173D This code typically indicates a failure in identifying the mechanical or electronic key
Try to start the car without other electronic devices in close proximity to the steering column. 3. Faulty Hands-Free Antennas b173d peugeot
: On newer models like the 308 or 3008, a fault in the battery protection and management unit can mimic key recognition errors.
is a manufacturer-specific code for key identification failure . It usually points to a dead key battery or a module communication error rather than a major mechanical engine failure. If you need more help, could you tell me:
If both keys fail and throw code B173D, the problem lies within the car's internal receiving network. Step 3: Perform a Full BSI Hard Reset
Low vehicle battery voltage (below 12V12 cap V ) often triggers false immobilizer codes. ✅ Summary While this code can appear in any modern
+------------------------+ Enters Cabin +-------------------------+ | Smart Key / Remote | = = = (Wireless RF / LF) = = > | Proximity Antenna/Slot | | (Transponder Chip) | | (Ignition Barrel Coil) | +------------------------+ +------------+------------+ | | (Hardwired Link) v +------------------------+ Unlocks Starting +------------+------------+ | Engine Control ECU | < = = = (CAN-Bus Signal) = = = | Central BSI Module | | (Immobilizer Status) | | (Decodes Fault B173D) | +------------------------+ +-------------------------+ Primary Root Causes 1. Key Fob Battery Depletion or Signal Interference
To fix this code, a mechanic or a confident DIYer will typically follow these steps:
In Peugeot diagnostic systems (and generic OBD-II translations), the code is typically defined as:
Peugeot microprocessors can hang or freeze during a low-voltage start. A structural hardware reboot often clears ghost faults like B173D: It usually points to a dead key battery
(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:
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If the problem persists, use a diagnostic tool like Lexia/Diagbox to monitor live data parameters. Check if the BSI changes status when a key is physically inserted into the reader slot. If the data stream shows no change, the key reader coil or its wiring harness behind the dashboard panel may be unplugged, damaged, or shorted.
Remember the golden rule of owning a modern diesel:
The B173D is a diesel engine code used in some Peugeot models (notably older 1.9–2.0L diesel variants). Below is a concise, structured article covering what it is, specifications, maintenance tips, and common faults.