P0406 – Meaning, Causes, Symptoms, & Fixes
Code P0406 Definition
Exhaust Gas Recirculation Sensor “A” Circuit High
What Does P0406 Mean?
The P0406 code is the result of the exhaust gas circulation (EGR) sensor A having a high circuit voltage. This code is set when the ECM identifies the EGR voltage is higher than the specified range, thus triggering the check engine light to illuminate on the vehicle dashboard.
What Are the Symptoms of Code P0406?
- Check engine light
- Increased production of NOx emissions
- Decreased engine performance
- Engine stall
- Engine pinging upon acceleration or higher speeds
- Lower fuel economy
*No noticeable adverse conditions in some cases
What Causes Code P0406?
- Faulty EGR valve sensor
- Open/Shorted EGR sensor circuit
- Dirty EGR valve
- Disconnected wiring in EGR circuit
How Sersiou Is Code P0406? – Moderate
This trouble code will not prevent your vehicle from regular operation. Code P0406 has a variety of symptoms that could prevent your vehicle from running normally or increase the difficulty of driving. If this code persists, your vehicle should be capable of being driven to nearest dealership.
Code P0406 Common Diagnosis Mistakes
Prematurely replacing the EGR valve without visually inspecting the wiring of the EGR sensor circuit for disconnection.
- Tools Needed to Diagnose:
How to Diagnosis and Repair Code P0406:
- Check to see if there are any other codes along with P0406 and clear your Check Engine Light with FIXD.
- Check the freeze frame data for the load and associated temperature of your vehicle upon the code being set.
- Conduct a visual inspection of the EGR sensor circuit for shorted or disconnected wiring.
- Use FIXD to monitor the EGR while your engine is running and under load.
- Remove the carbon buildup within the EGR valve, this might be preventing it from opening or closing properly.
- If the problem persists, consider replacing the EGR valve.