OBD2 code P0405: EGR Sensor A Circuit Low
Exhaust gas recirculation (EGR) routes part of the exhaust back into the intake to lower combustion temperature and NOx.
Detected Root Component
EGR Valve
Technical Component Diagrams
EGR Valve Layout
Diag Expert technical diagram
EGR Valve Connector
Diag Expert technical diagram
Observed Symptoms
- Check engine light on
- EGR switched off
- Diesel: possibly reduced power
- Otherwise hardly noticeable
Possible Causes
- Wire or connector to the EGR valve open or shorted to ground
- Position sensor in the EGR valve faulty (usually one unit with the valve)
- Older Ford: DPFE sensor faulty
- Shared 5 V reference shorted
Tools Required
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Parts likely to be the cause (Vanne EGR)
Vanne EGR
Photo d'illustration : Vanne EGR
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Frequently asked questions about code P0405
What does code P0405 mean? ▾
OBD2 code P0405: EGR Sensor A Circuit Low. Exhaust gas recirculation (EGR) routes part of the exhaust back into the intake to lower combustion temperature and NOx.
What are the symptoms of code P0405? ▾
Code P0405 may cause: Check engine light on, EGR switched off, Diesel: possibly reduced power, Otherwise hardly noticeable. The intensity of these symptoms varies depending on the vehicle and driving conditions.
What causes code P0405? ▾
The most common causes of code P0405 are: Wire or connector to the EGR valve open or shorted to ground, Position sensor in the EGR valve faulty (usually one unit with the valve), Older Ford: DPFE sensor faulty, Shared 5 V reference shorted. A proper OBD2 diagnostic will pinpoint the exact cause.
Is it serious to drive with code P0405? ▾
Code P0405 has moderate severity (Warning). Short-term driving remains possible, but a prompt check is recommended to prevent worsening.
How do I fix code P0405? ▾
Start by reading the code with an OBD2 scanner, then follow the interactive decision tree on this page. Priority causes to check: Wire or connector to the EGR valve open or shorted to ground, Position sensor in the EGR valve faulty (usually one unit with the valve), Older Ford: DPFE sensor faulty, Shared 5 V reference shorted. Difficulty: Medium · Estimated time: 30-60min.