Technical Description of OBD-II Trouble Code
Leak in the Intake Air System
What does that signify?
This is a generic diagnostic trouble code related to the powertrain, which applies to all makes and models from 1996 onwards. However, the specific troubleshooting steps may vary depending on the vehicle.
Trouble code P2279 indicates that there is an air leak on the “metered” side of the intake manifold. More air is entering the intake manifold than what is suggested by the mass airflow or MAP (manifold absolute pressure) sensor.
The engine uses a mass airflow sensor or MAP sensor (on older models) to determine the amount of air entering the intake manifold. The mass airflow sensor utilizes a “hot wire” for this purpose, while the MAP sensor measures the pressure within the manifold.
The engine control module (ECM) heats the wire to a specific temperature and maintains it by adjusting the voltage to the hot wire based on the amount of air passing through. This varying voltage serves as a signal indicating the volume of air passing through the wire.
An intake air temperature sensor allows the ECM to compensate for temperature changes. The ECM then adjusts the injector timing to maintain the fuel/air ratio, while the oxygen sensor confirms and maintains the fuel/air ratio.
When there is a disparity between the mass airflow, intake air temperature, and oxygen sensor readings, a leak is detected and the code P2279 is triggered.
Air leaks at the air filter or hoses leading up to the mass airflow sensor (MAF) or throttle body are not a concern. The leak is present between the mass airflow sensor or throttle body and the manifold.
Symptoms
An air leak is one of the most problematic issues in a fuel-injected engine. Precise control of the air/fuel ratio is necessary for proper operation. Symptoms of a P2279 engine code may include:
Potential Causes
Potential causes for this engine code may include:
Diagnostic and Repair Procedures
NOTE: Exercise caution when using unlit propane to detect a leak. We are not responsible for any damage or injury that may result from its usage. If you have doubts about using propane, you can alternatively spray carb/choke cleaner on suspected areas or build your own smoke machine. There are alternatives to using propane.
Once the leak has been identified and corrected, use a standard code scanner to erase the code and reset the ECM.
This code can apply to any vehicle from 1996 onwards, but it appears to be more common in Vauxhall, Saab, Honda, Acura, and VW models.
