P0479 Audi 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 Audi 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.
Code P0479 Audi Description
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.
What are the Possible Causes of the DTC P0479 Audi?
- 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 Audi?
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 Audi 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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Frequently Asked Questions about P0479 Audi Code
1. What are the common symptoms of OBDII code P0479 in an Audi related to the Exhaust Pressure Control Valve Intermittent?
- Common symptoms include reduced engine performance, decreased fuel efficiency, and potential exhaust system malfunctions.
2. What are the possible causes of OBDII code P0479 in an Audi?
- The code P0479 in an Audi is typically triggered by issues with the exhaust pressure control valve, wiring problems, or faulty sensors.
3. How can I diagnose the Exhaust Pressure Control Valve Intermittent issue in my Audi?
- To diagnose the issue, you can use an OBDII scanner to read the trouble codes, visually inspect the valve and its wiring for any visible damage, and test the valve's functionality.
4. Can I continue driving my Audi with OBDII code P0479 triggered?
- It is not recommended to drive your Audi with the code P0479 triggered, as it can lead to further damage to the exhaust system and affect the overall performance of the vehicle.
5. How can I repair OBDII code P0479 related to the Exhaust Pressure Control Valve Intermittent in my Audi?
- Repairing the issue may involve replacing the exhaust pressure control valve, repairing or replacing damaged wiring, or resetting the fault codes after addressing any underlying problems.
6. Are there any common DIY solutions for fixing OBDII code P0479 in an Audi?
- While some simple wiring checks and resets can be done by DIY enthusiasts, it is recommended to consult a professional mechanic for a proper diagnosis and repair of the issue.
7. How much does it typically cost to repair OBDII code P0479 in an Audi?
- The cost of repair can vary depending on the specific cause of the issue, but it can range from a few hundred to over a thousand dollars, including parts and labor.
8. What are the long-term effects of ignoring OBDII code P0479 in an Audi?
- Ignoring the code P0479 can lead to increased emissions, decreased fuel efficiency, potential damage to the catalytic converter, and overall engine performance issues.
9. Can a faulty Exhaust Pressure Control Valve cause other OBDII codes to trigger in an Audi?
- Yes, a faulty exhaust pressure control valve can cause other related codes to trigger, such as P0478 or P0480, as well as potentially affecting the overall exhaust system performance.
10. Is it possible for the OBDII code P0479 to be a false alarm in an Audi?
- While rare, false alarms can occur with OBDII codes, so it is recommended to have the system checked by a professional to confirm the issue before proceeding with any repairs.
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