OBD-II Error Code P0406: EGR Sensor A High - How to Fix It

Q: What does error code P0406 mean?

P0406 indicates the EGR sensor 'A' circuit voltage is higher than expected. This usually means a faulty EGR valve, sensor, or wiring problem.

Q: Can I drive with a P0406 code?

Yes, but you may notice reduced fuel economy, rough idling, or poor acceleration. It's best to fix it soon to avoid emissions test failure or further engine issues.

Q: How much does it cost to fix P0406?

DIY cost is around $50–$200 for a new EGR valve. Professional repair can range from $200 to $600, including labor and diagnostics.

Q: Will cleaning the EGR valve fix P0406?

Sometimes, if carbon buildup is causing the valve to stick. However, if the sensor itself is faulty, cleaning won't help and replacement is needed.

Q: What tools do I need to fix P0406?

You'll need an OBD2 scanner, multimeter, basic hand tools, and possibly a vacuum pump. Safety gear like gloves and glasses is also recommended.

Abstract

Error code P0406 means your car's engine control module (ECM) detects that the signal from the EGR (Exhaust Gas Recirculation) position sensor is too high. This usually points to a faulty EGR valve, sensor, or a wiring issue, which can lead to increased emissions and poor engine performance.