P0406 Honda Code - Exhaust Gas Recirculation Valve Position Sensor Circuit High Voltage
Quick Answer
The P0406 diagnostic trouble code for Honda vehicles indicates an issue with the Exhaust Gas Recirculation (EGR) valve position sensor circuit registering high voltage. Common causes include Faulty EGR Valve Position Sensor: The most common cause of the P0406 code is a malfunctioning EGR valve position sensor that is sending incorrect voltage readings to the ECM, Wiring Issues: Corrosion, damage, or poor connections in the wiring harness connected to the EGR valve position sensor can lead to high voltage readings, EGR Valve Stuck Open: A stuck open EGR valve can cause the sensor to detect high voltage, triggering the P0406 code. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.
- What it means
- P0406 Honda indicates Exhaust Gas Recirculation Valve Position Sensor Circuit High Voltage.
- Common causes
- Common causes include Faulty EGR Valve Position Sensor: The most common cause of the P0406 code is a malfunctioning EGR valve position sensor that is sending incorrect voltage readings to the ECM, Wiring Issues: Corrosion, damage, or poor connections in the wiring harness connected to the EGR valve position sensor can lead to high voltage readings, EGR Valve Stuck Open: A stuck open EGR valve can cause the sensor to detect high voltage, triggering the P0406 code.
- Severity
- Moderate - service should be scheduled soon.
- Can I drive?
- The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.
Code P0406 Honda Description
The P0406 diagnostic trouble code for Honda vehicles indicates an issue with the Exhaust Gas Recirculation (EGR) valve position sensor circuit registering high voltage. The EGR system is responsible for recirculating a portion of the exhaust gases back into the intake manifold to reduce emissions and control combustion temperatures. The EGR valve position sensor monitors the position of the EGR valve and sends this information to the engine control module (ECM). When the sensor detects a voltage higher than the specified range, it triggers the P0406 code.
Common Causes of P0406 Honda
- Faulty EGR Valve Position Sensor: The most common cause of the P0406 code is a malfunctioning EGR valve position sensor that is sending incorrect voltage readings to the ECM.
- Wiring Issues: Corrosion, damage, or poor connections in the wiring harness connected to the EGR valve position sensor can lead to high voltage readings.
- EGR Valve Stuck Open: A stuck open EGR valve can cause the sensor to detect high voltage, triggering the P0406 code.
- ECM Malfunction: In rare cases, a malfunctioning ECM may be incorrectly interpreting the sensor's readings and triggering the code.
- Carbon Buildup: Excessive carbon buildup in the EGR system can also affect the sensor's ability to accurately detect the valve's position.
Symptoms of P0406 Honda
- Check Engine Light: The most common symptom associated with the P0406 code is the illumination of the check engine light on the vehicle's dashboard.
- Rough Idling: The engine may experience rough idling or stalling when the EGR valve is stuck open, affecting overall engine performance.
- Decreased Fuel Efficiency: A faulty EGR valve position sensor can lead to decreased fuel efficiency as the engine struggles to maintain optimal combustion.
- Increased Emissions: High levels of emissions may be detected during emissions testing due to the EGR system not functioning properly.
- Engine Knocking: In severe cases, engine knocking or pinging may occur, indicating potential damage to the engine.
How to Fix P0406 Honda
- Diagnostic Testing: Begin by using a diagnostic scanner to retrieve the trouble code and perform a thorough inspection of the EGR system and related components.
- Check EGR Valve Position Sensor: Test the EGR valve position sensor for proper functionality and replace it if necessary.
- Inspect Wiring: Check the wiring harness for any signs of damage, corrosion, or poor connections, and repair or replace as needed.
- Clean or Replace EGR Valve: Clean the EGR valve to remove any carbon buildup that may be affecting its operation. If cleaning is not effective, consider replacing the EGR valve.
- Clear Codes and Test Drive: Clear the trouble code from the ECM, reset the system, and test drive the vehicle to ensure the issue has been resolved.
Cost to Fix P0406 Honda
The cost of repairing a P0406 code on a Honda vehicle can vary depending on the specific model, year, and extent of the issue. In general, the cost of parts such as a new EGR valve position sensor or EGR valve can range from $100 to $300. Labor costs for diagnosis and repair can add an additional $150 to $300, bringing the total repair cost to around $250 to $600. It's important to note that labor rates at auto repair shops can vary, so it's advisable to check with local shops for a more accurate estimate based on your location and vehicle.
When is the Code Detected?
Need more information about the P0406 Honda code?
Need more information on how to fix the P0406 Honda code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the P0406 Honda code diagnosed by a professional: Find a repair shop in your area
Frequently Asked Questions about P0406 Honda Code
No Frequently Asked Questions about P0406 Honda Code found.
Discuss the causes and fixes for P0406 Honda OBDII Code
Code P0406 Honda comments
No comments found for this page.
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.