P0406 is a general ODB-II trouble code which would indicate that there is a default within the exhaust gas recirculation EGR circuit. This trouble code is similar to P0400, P0401, P0402, P0403, P0404, P0405, P0407, P0408, P0409.
The P0406 error code can be identified as Exhaust Gas Recirculation Sensor “A” Circuit High.
What Does Code p0406 Mean?
Diagnostic trouble code (DTC) P0406 stands for “Exhaust Gas Recirculation Sensor A Circuit High.” It means that the powertrain control module (PCM) perceives a high voltage signal from the exhaust gas recirculation (EGR) position sensor.
The check engine code P0406 is triggered when the signal being sent back by the EGR position sensor to the PCM is higher than the specified range. The check engine light will activate as the PCM sets this code.
Code P0406 errors is triggered that the EGR Valve Position Sensor is giving voltage readings that are too high, usually above the 4.0 to 4.5 V range.
The exhaust gas recirculation (EGR) system recycles a small amount of exhaust gas from the exhaust system (usually no more than 10 percent) and mixes it with the intake manifold air entering into the combustion chambers.
The addition of this inert (or non-combustible) exhaust gas limits the peak combustion temperatures to a range that is below 2500° F, where the formation of nitrogen oxide (NOx) is know to occur.
In some cases where the engine is pinging and/or knocking badly from a severe lack of EGR flow, misfires can take place which allow raw hydrocarbons (HC) to be released from the tailpipe.
Potential Causes of a p0406 Code
The potential causes of a P0406 code include as below:
- EGR sensor signal circuit shorted to B+ (battery voltage)
- sensor ground circuit open EGR sensor signal circuit open
- Bad EGR (internal failure on EGR sensor or solenoid) Debris caught in the valve and holding it open or closed
- Circuit issues, such as damaged wires or poor connections
- An issue with the PCM, such as software in need of an update
p0406 Code Symptoms
The potential symptoms of a P0406 code include as below:
- Illuminated check engine light.
- Failed emission test due to increased NOx emissions.
- Decreased engine performance.
- Engine pinging.
- Poor fuel economy.
- Engine stalling.
How to Fix p0406
The diagnostic and repair processes of the P0406 code may vary based on the vehicle’s make and model. Fixing this DTC is a task best left to the professionals if you are not that confident with your automotive know-how and DIY skills
The first step to resolving the P0406 code is diagnosis. Pinpoint the underlying cause of the issue. Then, with the help of online auto repair resources and guides, figure out the correct way to fix the DTC.
You can look up confirmed P0406 fixes and other useful information in a vehicle-specific factory repair subscription.
Refer to More details below.
Engine Control Module :
If everything is alright with the Crankshaft Position Sensor, then there is surely some defect in Engine Control Module. Get it replaced before the situation gets worse.
Fuel Pressure Regulator:
P0406 code can display due to some issues in the Fuel Pressure Regulator. So, it is very important to replace the Fuel Pressure Regulator with us at equitable prices.
EGR Valve Gasket:
Do you remember when was the last time you got your car EGR Valve Gasket checked up? A faulty EGR Valve Gasket can cause a lot of issues like displaying P0406 code.
Powertrain Control Module:
There can be some issues with the Powertrain Control Module due to which you may see P0406 code appearing over and over again.
Air Intake Temperature Sensor:
Are you facing some faults in your Air Intake temperature Sensor? Don’t worry and get them replaced or else P0406 code can turn up.
Engine Coolant Temperature Sensor:
A common cause behind this P0406 error code can be some fault in the Engine Coolant Temperature Sensor. So, it will be a good decision to replace them now.
How Much Does It Cost to Fix a p0406 Code?
To fix a P0406 code, which indicates a problem with the Exhaust Gas Recirculation (EGR) sensor circuit, you can expect to pay between $100 and $400 depending on the cause and whether you need to replace the sensor itself, clean carbon buildup, or repair wiring; labor costs can vary depending on your location and mechanic.
P0406 code repair costs:
- Sensor replacement: If the EGR position sensor needs replacing, the part itself can range from $50 to $150, with additional labor costs for installation.
- Cleaning carbon buildup: Sometimes, a simple cleaning of carbon deposits on the EGR valve can resolve the issue, which may be a less expensive option.
- Wiring issues: If the problem lies with the wiring harness, repairs might involve replacing damaged wires or connectors, adding to the cost.