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P2279 is a diagnostic trouble code (DTC) for "Intake Air System Leak". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.
Intake Air System Leak
P2279 is an OBD-II generic code for the engine control module (ECM) detecting a vacuum leak into the engine. This means that unmetered air is entering the engine without the engine sensing it going through the mass air flow sensor and throttle body.
The engine control module (ECM) calculates the amount of air going into the engine through the positive crankcase ventilation (PCV) system. If the amount of air is more than expected then the Check Engine Light will come on and code P2279 is set.
The ECM learns the throttle opening angle and stores it in memory. If the throttle body is cleaned or adjusted without the throttle relearn process performed, then the code may be set.
The PCV valve or hose is leaking or cracked causing excess air to get into the engine unmetered.
The Check Engine Light will be illuminated and the code is set in the ECM memory as a fault.
The engine may run very rough and stall if the vacuum leak is major.
The engine may run lean and misfire.
The fuel mileage may be more than before failure since the ECM will try and compensate for the excess air in the engine detected by the O2 sensors.
Scans for codes and documents any codes in the ECM, then looks at the freeze frame data for failure
Listens to the engine for any vacuum leaks, broken, or loose vacuum hoses or air inlet hoses
Removes the PCV valve and checks to make sure it is not stuck in the open position
Checks the throttle body to see if it was recently cleaned and allows relearning of the throttle position, then clears the codes and retests
Clearing ECM memory codes before checking the freeze frame data for the main failure problem, so the failure may be duplicated and repaired
Cleaning the throttle body and not relearning the throttle position again
Adjusting the throttle plates to compensate for a vacuum leak
Code P2279 is a code indicating that the ECM is detecting that the engine has too much air entering and sees this as a vacuum leak. An engine running with too much air will run lean and cause the engine to run rough and stall at low engine speeds.
Code P2279 can be from any kind of vacuum leak in an engine. Some vehicle manufacturers may use different lean codes instead of this code. The code can be generated from a throttle body or idle air control valve cleaning. This can cause the engine to have to lower the throttle plate to maintain the correct idle speed and see this as excess air entering the engine causing the P2279 code to turn on. A simple relearn of the base idle will fix most of these problems.
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