P0406

Symptoms

• Check Engine Light Is On
• Increased fuel consumption
• Engine knocking and knocking under load
• Unstable idle
• Loss of power when accelerating
• Increased NOx content in the exhaust
• Emissions inspection failure

Causes

• Short circuit in the EGR sensor wiring to power
• Faulty EGR valve position sensor
• Contamination or mechanical failure of the EGR valve
• Open circuit in the sensor grounding circuit
• Problems with the connector (oxidation, corrosion)
• ECU malfunction (rare)

How to Fix

1. Read all error codes with the scanner and write them down
2. Check the voltage in the EGR sensor circuit with the ignition on
3. Check the wiring and connector of the sensor for breaks, short circuits, oxidation
4. Measure sensor resistance and compare with specification
5. Clean the valve and EGR channels from carbon deposits
6. Replace the EGR position sensor if the fault is confirmed
7. Reset the code and test drive to check the fix

Related codes

Error P0406 by Vehicle Brand