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P0479 Volkswagen Code - Exhaust Pressure Control Valve Intermittent

Quick Answer

The P0479 diagnostic trouble code (DTC) in a Volkswagen indicates an issue with the Exhaust Pressure Control Valve (EPCV) that is intermittent. Common causes include Faulty EPCV: The most common cause of the P0479 code is a malfunctioning Exhaust Pressure Control Valve, Wiring or Electrical Issues: Corrosion, damage, or loose connections in the wiring harness related to the EPCV can also trigger this code, Exhaust Pressure Sensor Problem: A malfunctioning exhaust pressure sensor can cause the EPCV to operate intermittently, leading to the P0479 DTC. 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
P0479 Volkswagen indicates Exhaust Pressure Control Valve Intermittent.
Common causes
Common causes include Faulty EPCV: The most common cause of the P0479 code is a malfunctioning Exhaust Pressure Control Valve, Wiring or Electrical Issues: Corrosion, damage, or loose connections in the wiring harness related to the EPCV can also trigger this code, Exhaust Pressure Sensor Problem: A malfunctioning exhaust pressure sensor can cause the EPCV to operate intermittently, leading to the P0479 DTC.
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.
What is this?
Table of contents Created and updated by William Orellana on Sep 12, 2024
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Code P0479 Volkswagen Description

The P0479 diagnostic trouble code (DTC) in a Volkswagen indicates an issue with the Exhaust Pressure Control Valve (EPCV) that is intermittent. The EPCV is responsible for regulating the exhaust pressure in the vehicle's exhaust system. When this valve malfunctions or operates intermittently, it can lead to a variety of performance issues in the vehicle.

OBDII Code P0479 Volkswagen - Exhaust Pressure Control Valve Intermittent
P0479 Volkswagen Code - Exhaust Pressure Control Valve Intermittent

Common Causes of P0479 Volkswagen

  1. Faulty EPCV: The most common cause of the P0479 code is a malfunctioning Exhaust Pressure Control Valve.
  2. Wiring or Electrical Issues: Corrosion, damage, or loose connections in the wiring harness related to the EPCV can also trigger this code.
  3. Exhaust Pressure Sensor Problem: A malfunctioning exhaust pressure sensor can cause the EPCV to operate intermittently, leading to the P0479 DTC.
  4. Vacuum Leaks: Any vacuum leaks in the exhaust system can disrupt the proper operation of the EPCV.

Symptoms of P0479 Volkswagen

  1. Check Engine Light: The most common symptom associated with the P0479 code is the illumination of the check engine light on the dashboard.
  2. Reduced Fuel Efficiency: A malfunctioning EPCV can lead to decreased fuel efficiency in the vehicle.
  3. Poor Engine Performance: The vehicle may experience rough idling, hesitation, or lack of power due to the irregular operation of the EPCV.
  4. Increased Emissions: A faulty EPCV can cause an increase in emissions, potentially leading to a failed emissions test.

How to Fix P0479 Volkswagen

  1. Diagnose the Issue: Use a diagnostic scan tool to retrieve the DTC and pinpoint the exact cause of the problem.
  2. Inspect EPCV and Wiring: Check the Exhaust Pressure Control Valve and its wiring for any signs of damage or corrosion.
  3. Test Exhaust Pressure Sensor: Verify the functionality of the exhaust pressure sensor to ensure it is working correctly.
  4. Replace Faulty Components: If the EPCV, wiring, or exhaust pressure sensor is found to be faulty, replace them with new components.
  5. Clear Codes and Test Drive: Clear the DTC from the vehicle's memory and test drive the vehicle to ensure that the issue has been resolved.

Cost to Fix P0479 Volkswagen

The cost of repairing the Exhaust Pressure Control Valve Intermittent issue in a Volkswagen can vary depending on the specific components that need to be replaced and the labor rates in your area. On average, the repair cost for this issue can range from $200 to $500, including parts and labor. However, it's essential to keep in mind that diagnosis time and labor rates can vary significantly, so it's advisable to check with local auto repair shops for a more accurate estimate. Labor rates typically range from $80 to $150 per hour, with rates potentially higher at dealerships or in metropolitan areas.

What does this mean?

Tech Notes for P0479 Volkswagen

Check the Exhaust Back Pressure Valve (EBPV) butterfly valve is opening and closing freely and not sticking. If it seems to move freely you can then check the connector and circuit for the EBPV solenoid.

When is the Code Detected?

Problems with either the Exhaust Back Pressure (EBP) Device or the tube between the exhaust manifold and the EBP sensor can be detected during the exhaust back pressure step test, in which the Engine Control Module (ECM) commands and then measures a specific preprogrammed pressure and then measures time for pressure decay during the engine running test.

If the ECM detects an Exhaust Back Pressure (EBP), Engine Oil Temperature (EOT) or Intake Air Temperature (IAT) sensor fault it will disable the exhaust back pressure regulator.

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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 P0479 Volkswagen Code

1. What are the common symptoms of OBDII code P0479 in a Volkswagen related to the Exhaust Pressure Control Valve Intermittent issue?

The common symptoms include reduced engine power, decreased fuel efficiency, and the illumination of the check engine light.

2. What are the possible causes of the Exhaust Pressure Control Valve Intermittent issue triggering OBDII code P0479 in a Volkswagen?

Common causes may include a faulty exhaust pressure control valve, wiring issues, a damaged exhaust pressure sensor, or a clogged DPF (diesel particulate filter).

3. How can I diagnose the Exhaust Pressure Control Valve Intermittent issue causing OBDII code P0479 in my Volkswagen?

Diagnosis involves using an OBDII scanner to retrieve the code, visually inspecting the exhaust pressure control valve and sensor, and checking for any wiring issues or blockages in the DPF.

4. Can I continue driving my Volkswagen with OBDII code P0479 related to the Exhaust Pressure Control Valve Intermittent issue?

It is not recommended to drive your vehicle with this issue as it can lead to further damage and potentially unsafe driving conditions. It's best to address the problem promptly.

5. What are some repair tips for resolving the Exhaust Pressure Control Valve Intermittent issue triggering OBDII code P0479 in a Volkswagen?

Repair tips may include replacing the exhaust pressure control valve, repairing any damaged wiring, cleaning or replacing the DPF, and ensuring proper installation of components.

6. How much does it typically cost to repair the Exhaust Pressure Control Valve Intermittent issue associated with OBDII code P0479 in a Volkswagen?

The cost of repair can vary depending on the exact cause of the issue, but it may range from a few hundred to over a thousand dollars, including parts and labor.

7. Can I reset the check engine light after fixing the Exhaust Pressure Control Valve Intermittent issue triggering OBDII code P0479 in my Volkswagen?

Yes, once the issue is resolved, you can reset the check engine light using an OBDII scanner or by disconnecting the car's battery for a few minutes.

8. How often does the Exhaust Pressure Control Valve Intermittent issue leading to OBDII code P0479 occur in Volkswagen vehicles?

The occurrence of this issue can vary depending on driving habits, maintenance, and vehicle age, but it is relatively common in diesel-powered Volkswagen models.

9. Is it possible to prevent the Exhaust Pressure Control Valve Intermittent issue triggering OBDII code P0479 in my Volkswagen?

Regular maintenance, such as timely replacement of filters and proper driving habits, can help prevent issues related to the exhaust system and reduce the likelihood of triggering this OBDII code.

10. Can I fix the Exhaust Pressure Control Valve Intermittent issue causing OBDII code P0479 in my Volkswagen myself, or do I need to take it to a professional mechanic?

While some DIY enthusiasts may attempt the repairs themselves, it is often recommended to seek the expertise of a professional mechanic, especially when dealing with complex exhaust system components and sensors.

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