AdBlue (SCR) system

The B173D error code in Peugeot vehicles refers to a specific fault within the vehicle's electronic architecture, most commonly associated with the or the Start-Stop (STT) battery management system. 🛠️ Understanding the B173D Code

Related Codes Often Seen Together

Less common, but if there is corrosion in a wiring harness connector causing "noise" on the CAN-BUS data lines, the data packets become garbled, and the BSI cannot interpret the identification signals.

: The chip inside the key may be damaged or have lost its synchronization with the vehicle. Immobilizer Antenna Issues

Broken Wiring (Most Common): The wiring harness that passes from the door frame into the mirror housing is subject to constant bending every time the door is opened and closed. Over time, these wires can fray and snap.
Corrosion: Water ingress in the mirror connector plugs can cause corrosion on the pins, preventing electrical contact.
Failed Mirror Actuator: The small electric motor inside the mirror housing (the actuator) may have burned out or seized due to age or debris.
Damaged Door Loom: In many Peugeot models (like the 207, 208, 307, or 308), the wiring loom inside the door itself can become damaged by the window regulator mechanism or the door latch.

. This is a manufacturer-specific code generated by the Built-in Systems Interface (BSI) when it fails to communicate with or verify the transponder in your key. The Automotive Technician Common Symptoms Intermittent Non-Start : The car may fail to start on the first few attempts. Key Recognition Failure b173d peugeot

Peugeot BlueHDi engines are notorious for carbon buildup. Because the glow plugs extend into the combustion chamber, they become crusted with hard, black carbon. This carbon can:

Remove the sensor (usually one T20 Torx screw or a push-clip).
Remove the rubber protective cap from the sensor’s nose.
Use a cotton swab with isopropyl alcohol (not brake cleaner or WD-40) to gently clean the internal sensing element.
Reassemble and clear the code. Drive for 20 minutes. If the code returns, proceed to the next step.

Pin 1 (usually Black): Ground (0 ohms to chassis).
Pin 2 (usually Red/Yellow): 12V power supply from BSI (should be ~12V).
Pin 3 (usually other color): Signal wire to BSI (should show ~5V reference).

B173d Peugeot File

AdBlue (SCR) system

Related Codes Often Seen Together

: The chip inside the key may be damaged or have lost its synchronization with the vehicle. Immobilizer Antenna Issues

Broken Wiring (Most Common): The wiring harness that passes from the door frame into the mirror housing is subject to constant bending every time the door is opened and closed. Over time, these wires can fray and snap.
Corrosion: Water ingress in the mirror connector plugs can cause corrosion on the pins, preventing electrical contact.
Failed Mirror Actuator: The small electric motor inside the mirror housing (the actuator) may have burned out or seized due to age or debris.
Damaged Door Loom: In many Peugeot models (like the 207, 208, 307, or 308), the wiring loom inside the door itself can become damaged by the window regulator mechanism or the door latch.

Peugeot BlueHDi engines are notorious for carbon buildup. Because the glow plugs extend into the combustion chamber, they become crusted with hard, black carbon. This carbon can:

Remove the sensor (usually one T20 Torx screw or a push-clip).
Remove the rubber protective cap from the sensor’s nose.
Use a cotton swab with isopropyl alcohol (not brake cleaner or WD-40) to gently clean the internal sensing element.
Reassemble and clear the code. Drive for 20 minutes. If the code returns, proceed to the next step.

Pin 1 (usually Black): Ground (0 ohms to chassis).
Pin 2 (usually Red/Yellow): 12V power supply from BSI (should be ~12V).
Pin 3 (usually other color): Signal wire to BSI (should show ~5V reference).