AutoCodesVolkswagen – P0479 Volkswagen

P0479 Volkswagen Code - Exhaust Pressure Control Valve Intermittent

Quick Answer

Exhaust Back Pressure Regulator - Is a variable position valve that controls exhaust back pressure during cold ambient temperatures to increase cab heat and decrease the amount of time needed to defrost the windshield. Common causes include Faulty Exhaust Back Pressure Valve, Exhaust Back Pressure Valve harness is open or shorted, Exhaust Back Pressure Valve circuit poor electrical connection. 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 Exhaust Back Pressure Valve, Exhaust Back Pressure Valve harness is open or shorted, Exhaust Back Pressure Valve circuit poor electrical connection.
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 1,418
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Apr 25, 2019
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Code P0479 Volkswagen Description

Exhaust Back Pressure Regulator - Is a variable position valve that controls exhaust back pressure during cold ambient temperatures to increase cab heat and decrease the amount of time needed to defrost the windshield. The Engine Control Module (ECM) uses the measured exhaust back pressure, (ambient) intake air temperature, engine oil temperature and engine load to determine the desired exhaust back pressure. Valve position is controlled by switching the output signal circuit to 12 volts inside the ECM. On/off time is modulated from 0 to 99 % dependent upon the exhaust back pressure desired.
Upon each initial engine start-up, the ECM exercises the exhaust back pressure valve by commanding it to cycle on and off once. If upon start-up the temperature of intake air sensed by the Intake Air Temperature (IAT) sensor is < 37°F (5°C) and the oil temperature sensed by the Engine Oil Temperature (EOT) sensor is between 32°-140°F (0-60°C) it will continue to keep the back pressure valve partially closed. As the oil temperature rises during engine operation, the ECM will control the valve in response to the rising oil temperature.
OBDII Code P0479 Volkswagen - Exhaust Pressure Control Valve Intermittent - AutoCodes.com
P0479 Volkswagen Code - Exhaust Pressure Control Valve Intermittent

What are the Possible Causes of the DTC P0479 Volkswagen?

  • Faulty Exhaust Back Pressure Valve
  • Exhaust Back Pressure Valve harness is open or shorted
  • Exhaust Back Pressure Valve circuit poor electrical connection

How to Fix the DTC P0479 Volkswagen?

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.

Code Tech Notes

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0479 Volkswagen 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 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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