AutoCodes – Pontiac – P0406 Pontiac

P0406 Pontiac Code - Exhaust Gas Recirculation Position Sensor Circuit High Voltage

Quick Answer

The Engine Control Module (ECM) uses the Exhaust Gas Recirculation (EGR) position sensor to determine the position of the EGR valve. Common causes include Faulty Exhaust Gas Recirculation (EGR) Valve, Exhaust Gas Recirculation Valve harness is open or shorted, Exhaust Gas Recirculation Valve circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P0406 Pontiac indicates Exhaust Gas Recirculation Position Sensor Circuit High Voltage.
Common causes: Common causes include Faulty Exhaust Gas Recirculation (EGR) Valve, Exhaust Gas Recirculation Valve harness is open or shorted, Exhaust Gas Recirculation Valve circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 1,726

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Mar 24, 2024

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

The Engine Control Module (ECM) uses the Exhaust Gas Recirculation (EGR) position sensor to determine the position of the EGR valve. The ECM sends a reference voltage through the 5 V reference circuit to the EGR position sensor. The ECM provides a voltage return path for the sensor through the low reference circuit. A variable voltage signal, based on the EGR valve position, is sent from the sensor to the ECM through the EGR position sensor signal circuit. The Diagnostic Trouble Code (DTC) will be set when the ECM detects that the EGR position sensor voltage is greater than 4.8 V for greater than 5 s.

OBDII Code P0406 Pontiac - Exhaust Gas Recirculation Position Sensor Circuit High Voltage - AutoCodes.com — P0406 Pontiac Code - Exhaust Gas Recirculation Position Sensor Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P0406 Pontiac?

Faulty Exhaust Gas Recirculation (EGR) Valve
Exhaust Gas Recirculation Valve harness is open or shorted
Exhaust Gas Recirculation Valve circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P0406 Pontiac?

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 Pontiac 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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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.

Frequently Asked Questions about P0406 Pontiac Code

1. What does the OBDII code P0406 mean for a Pontiac?

P0406 indicates that the Exhaust Gas Recirculation (EGR) position sensor circuit is reporting a voltage higher than expected by the vehicle's engine control module (ECM).

2. What are the common symptoms of code P0406?

Typical symptoms include poor engine performance, rough idling, reduced fuel efficiency, engine hesitation, or the check engine light turning on.

3. What causes the P0406 code in a Pontiac?

Common causes include a faulty EGR position sensor, wiring issues such as damaged or corroded connectors, carbon buildup in the EGR valve, or a malfunctioning ECM.

4. Can I drive my Pontiac with the P0406 code?

While the vehicle may still be drivable, it can experience reduced performance and efficiency. Prolonged driving without addressing the issue may lead to further damage.

5. How is the P0406 code diagnosed?

A mechanic will use a scan tool to read the code, inspect the EGR valve and position sensor, check the wiring and connectors, and test the sensor voltage for abnormalities.

6. How can I fix the P0406 code on my Pontiac?

Repairs may include cleaning or replacing the EGR valve, repairing or replacing damaged wiring, replacing the EGR position sensor, or updating the ECM software.

7. What tools are needed to repair the P0406 issue?

Common tools include a diagnostic scanner, a multimeter for testing voltage, and basic hand tools for inspecting and replacing components like the EGR valve or sensor.

8. How much does it cost to repair the P0406 code?

Repair costs vary, but replacing the EGR valve or sensor typically costs between $150 and $400, including parts and labor. Wiring repairs may cost less.

9. Can a dirty EGR valve cause the P0406 code?

Yes, carbon buildup inside the EGR valve can cause the position sensor to send incorrect voltage signals, triggering the P0406 code.

10. Is the P0406 code related to emissions issues?

Yes, the EGR system is part of the emissions control system, and issues with it can increase NOx emissions and cause the vehicle to fail an emissions test.