Understanding Volkswagen P2279: Intake Air System Leak Diagnostics

Understanding Volkswagen P2279: Intake Air System Leak Diagnostics

The diagnostic trouble code (DTC) P2279 on Volkswagen vehicles indicates an “Intake Air System Leak.” Specifically, this code means that the engine control module (ECM) has detected more air entering the intake manifold than what the mass airflow sensor or manifold absolute pressure (MAP) sensor is measuring. This suggests there is an unmetered air leak in the intake system after the mass airflow sensor.

How Serious is This Issue?

Severity: Moderate to High

While not immediately critical, the P2279 code should not be ignored. If left unaddressed, it could potentially lead to more severe engine problems over time. The issue affects the engine’s air intake system, which is crucial for proper combustion and overall engine performance.

Is it Safe to Drive with This DTC Code?

It is generally not recommended to drive for extended periods with the P2279 code active. While the vehicle may still be operational, continuing to drive could potentially cause further damage to the engine or fuel system components. Short trips to a repair facility are usually acceptable, but it’s best to address the issue promptly.

Symptoms and Common Causes of This DTC Code


  • Illuminated Check Engine Light
  • Rough idling
  • Decreased engine performance
  • Potential misfires
  • Reduced fuel economy
  • Engine stalling
  • Lack of power
  • Dead spots on the throttle during acceleration

Common Causes

  • Faulty or loose intake components
  • Cracked or damaged intake manifold
  • Vacuum leaks
  • Faulty PCV (Positive Crankcase Ventilation) system
  • Damaged or disconnected intake hoses
  • Faulty intake manifold gaskets
  • Loose oil cap

How Can I Fix It?

Fixing the P2279 code typically involves the following steps:

  1. Diagnose the exact cause using a professional-grade OBD-II scanner.
  2. Inspect the intake system for visible damage or loose connections.
  3. Perform a smoke test to identify any leaks.
  4. Check and tighten the oil cap.
  5. Inspect and replace any damaged vacuum lines or hoses.
  6. Clean or replace the mass airflow sensor if necessary.
  7. Replace faulty components as needed (e.g., PCV valve, intake manifold gasket).
  8. Clear the code and perform a test drive to ensure the problem is resolved.

Can I Fix This DTC Code Myself?

While some basic diagnostic steps can be performed at home, fixing this issue often requires specialized tools and knowledge of the intake system. Unless you have advanced automotive repair experience, it’s recommended to have a professional mechanic diagnose and repair this issue.

What Parts Might Need Replacement and How Much Will the Repair Cost?

Potential Parts for Replacement

  • Intake hoses or tubes
  • PCV valve
  • Intake manifold gasket
  • Mass airflow sensor
  • Vacuum lines

Estimated Repair Costs

  • Diagnosis: $75-$150
  • PCV valve replacement: $50-$250
  • Intake manifold gasket replacement: $200-$600
  • Mass airflow sensor replacement: $150-$400

Note that costs can vary significantly depending on the specific vehicle model and the root cause of the issue.

Will the Repair Be Expensive?

The repair cost can range from moderate to expensive, depending on the underlying cause. If it’s a simple hose replacement or PCV valve issue, costs may be relatively low. However, if major components like the intake manifold gasket need replacement, the repair could be more expensive.

Can I Reset the DTC Code Myself?

While it’s possible to clear the code using an OBD-II scanner, this should only be done after the underlying issue has been fixed. Simply clearing the code without addressing the root cause will likely result in the code returning quickly.

Will It Affect Performance or Fuel Efficiency?

Yes, the P2279 code can negatively impact both performance and fuel efficiency. The engine may run less smoothly, potentially misfire, and consume more fuel than normal due to the incorrect air-fuel mixture caused by the unmetered air entering the system.

How Can I Prevent It in the Future?

To help prevent this issue in the future:

  • Follow the manufacturer’s recommended maintenance schedule.
  • Regularly inspect intake system components for wear or damage.
  • Address any engine performance issues promptly.
  • Ensure proper installation of aftermarket intake components.
  • Use high-quality replacement parts when repairs are needed.
  • Have regular inspections of the intake system performed by a qualified mechanic.

By staying proactive with maintenance and addressing any warning signs early, you can help reduce the likelihood of experiencing this and other intake system-related issues in your Volkswagen vehicle.


  1. YouTube Video
  2. OBD-Codes
  3. TrocForums
  4. RepairPal
  5. Ross-Tech Forum
  6. YouTube Video
  7. VWVortex Forum
  8. CarParts Blog
  9. KBB OBD-II Codes
  10. JustAnswer VW
  11. GolfMK6 Forum
  12. JustAnswer Audi
  13. VWVortex Forum

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