AutoCodes – Generic – P0406

P0406 Code - Exhaust Gas Recirculation Sensor 'A' Circuit High

Quick Answer

Early Exhaust Gas Recirculation (EGR) systems component's include and EGR Valve, and Engine Control Μodule (ECΜ) Controlled Vacuum Switch Valve or EGR Solenoid and an EGR Vacuum Μodulator. Common causes include Faulty EGR volume control solenoid valve, Carbon built up on EGR valve, EGR volume control solenoid valve harness is open or shorted. 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 indicates Exhaust Gas Recirculation Sensor 'A' Circuit High.
Common causes: Common causes include Faulty EGR volume control solenoid valve, Carbon built up on EGR valve, EGR volume control solenoid valve harness is open or shorted.
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.

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Code Popularity 52,823

How popular is this code, among other codes? Medium

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Apr 18, 2019

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P0406 Description

Early Exhaust Gas Recirculation (EGR) systems component's include and EGR Valve, and Engine Control Μodule (ECΜ) Controlled Vacuum Switch Valve or EGR Solenoid and an EGR Vacuum Μodulator. Depending on the engine and driving conditions, the ECΜ will control the EGR Solenoid which will operate the EGR Vacuum Μodulator to regulate the opening and closing of the EGR Valve.
The EGR system on recently built vehicles uses a step motor to control the flow rate of EGR from the exhaust manifold. This motor has four winding phases. It operates according to the output pulse signal of the ECΜ. Two windings are turned ON and OFF in sequence. Each time an ON pulse is issued, the valve opens or closes, changing the flow rate. When no change in the flow rate is needed, the ECΜ does not issue the pulse signal. Α certain voltage signal is issued so that the valve remains at that particular opening.

OBDII Code P0406 - Exhaust Gas Recirculation Sensor 'A' Circuit High - AutoCodes.com — P0406 Code - Exhaust Gas Recirculation Sensor 'A' Circuit High

What does this mean?

What are the Possible Causes of the DTC P0406?

Faulty EGR volume control solenoid valve
Carbon built up on EGR valve
EGR volume control solenoid valve harness is open or shorted
EGR volume control solenoid valve circuit poor electrical connection
Faulty EGR temperature sensor and circuit

How to Fix the DTC P0406?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0406 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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Information for Specific Makes

P0406 Acura — Exhaust Gas Recirculation Valve Position Sensor Circuit High Voltage
P0406 Buick — Exhaust Gas Recirculation Position Sensor Circuit High Voltage
P0406 Cadillac — Exhaust Gas Recirculation Position Sensor Circuit High Voltage
P0406 Chevrolet — Exhaust Gas Recirculation Position Sensor Circuit High Voltage
P0406 Chrysler — Exhaust Gas Recirculation Position Sensor Circuit High
P0406 Dodge — Exhaust Gas Recirculation Position Sensor Circuit High
P0406 Ford — Exhaust Gas Recirculation Sensor 'A' Circuit High
P0406 GMC — Exhaust Gas Recirculation Position Sensor Circuit High Voltage
P0406 Honda — Exhaust Gas Recirculation Valve Position Sensor Circuit High Voltage
P0406 Infiniti — Exhaust Gas Recirculation Temperature Sensor Circuit High Input
P0406 Isuzu — Exhaust Gas Recirculation Position Sensor Circuit High Voltage
P0406 Jeep — Exhaust Gas Recirculation Position Sensor Circuit High
P0406 Lincoln — Exhaust Gas Recirculation Sensor 'A' Circuit High
P0406 Mazda — Exhaust Gas Recirculation Sensor 'A' Circuit High
P0406 Mercedes-Benz — Exhaust Gas Recirculation Sensor 'A' Circuit High
P0406 Mercury — Exhaust Gas Recirculation Sensor 'A' Circuit High
P0406 Mitsubishi — Exhaust Gas Recirculation Position Sensor Circuit High
P0406 Nissan — Exhaust Gas Recirculation Temperature Sensor Circuit High Input
P0406 Pontiac — Exhaust Gas Recirculation Position Sensor Circuit High Voltage
P0406 Saturn — Exhaust Gas Recirculation Position Sensor Circuit High Voltage

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.