OBD2 code P0403: EGR A Control Circuit/Open
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: pinging (petrol) or higher NOx
- Usually no loss of power
Possible Causes
- Connector at the EGR valve corroded or loose
- Broken control or supply wire
- Coil or motor in the EGR valve burnt out
- Driver in the engine module
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 P0403
What does code P0403 mean? ▾
OBD2 code P0403: EGR A Control Circuit/Open. 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 P0403? ▾
Code P0403 may cause: Check engine light on, EGR switched off: pinging (petrol) or higher NOx, Usually no loss of power. The intensity of these symptoms varies depending on the vehicle and driving conditions.
What causes code P0403? ▾
The most common causes of code P0403 are: Connector at the EGR valve corroded or loose, Broken control or supply wire, Coil or motor in the EGR valve burnt out, Driver in the engine module. A proper OBD2 diagnostic will pinpoint the exact cause.
Is it serious to drive with code P0403? ▾
Code P0403 has moderate severity (Warning). Short-term driving remains possible, but a prompt check is recommended to prevent worsening.
How do I fix code P0403? ▾
Start by reading the code with an OBD2 scanner, then follow the interactive decision tree on this page. Priority causes to check: Connector at the EGR valve corroded or loose, Broken control or supply wire, Coil or motor in the EGR valve burnt out, Driver in the engine module. Difficulty: Medium · Estimated time: 30-60min.