If the glow plug tests fine electrically, but the code persists, you may have carbon "bridging." The mechanic must:
: In Peugeot models (like the 308 or 5008), an old or undercharged car battery can cause the BSI to throw multiple "ghost" codes, including B173D, as it tries to conserve power . b173d peugeot
: Have your main car battery tested. If it is more than 3–5 years old, low voltage during startup can trigger B173D. If the glow plug tests fine electrically, but
Erase the B173D code, start the engine on a cold morning, and re-scan. If it returns immediately, the fault is permanent. Erase the B173D code, start the engine on
In rare cases (2015-2017 models), Peugeot released software updates to address false b173d alerts. Your local Peugeot dealer can update the BSI firmware. Cost is typically 0.5 hours of labor.
