Set your multimeter to the setting.
The architecture used in models like the Peugeot 207, 307, 308, and Partner relies heavily on sealed fuse boxes that are prone to localized environmental and physical wear: 1. Internal BSM (Engine Relay Unit) Failure
: Use a dedicated diagnostic tool (like Diagbox) to erase the code and see if it returns immediately upon turning the ignition.
Safety & Reliability
If you read zero or minimal resistance while the ignition is entirely off, the harness wire is shorted to a power source somewhere along the engine loom. Step 3: Check Control Module Communication Lines
Disclaimer: This blog post is for informational purposes only. Vehicle diagnostics can vary by model and year. Always consult a qualified mechanic for accurate repair advice.
If you encounter this code during a scan using tools like or Diagbox , consider these steps: a9b7 peugeot
While this code can appear on various PSA Group vehicles using similar BSI architecture, it is frequently documented on: Peugeot 208 (A9)
While this code can theoretically apply to several modules, on Peugeot models (especially the 208, 2008, 308, and 508), it is most frequently linked to issues with the or the Navigation/Radio system .
Every modern Peugeot depends heavily on its multiplexed architecture, managed primarily by the (the interior body control unit) and the BSM (the under-hood engine switching unit/fuse box). Set your multimeter to the setting
Typically results in a "Crank but No Start" condition, as the ignition positive signal is critical for powering essential engine management components. 2. Symptom Analysis Engine Non-Start:
The engine bay fuse box containing heavy-duty relays.
The BSI is usually located behind the glovebox or under the dashboard. A common fault on the Peugeot 307 is a clogged cabin air filter drain, leading to water dripping directly onto the BSI circuit board. Corroded pins on the CAN bus connector will generate permanent communication errors. Safety & Reliability If you read zero or
A bright warning light will shine on your dashboard.