P0405
Exhaust Gas Recirculation Sensor "A" Circuit Low
Exhaust Gas Recirculation Sensor "A" Circuit Low: the signal voltage is below the expected range. Without valid EGR feedback the ECU disables exhaust gas recirculation and may set further EGR codes.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- EGR position sensor failedCommon
- Wiring or connector faultPossible
- Connector pins corroded - high contact resistanceLess likely
Parts involved
- EGR Position Sensor
- EGR Sensor Wiring
P0405 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.