Check for intake leaks
Faulty Mass Air Flow (MAF) sensor
Faulty Positive Crankcase Ventilation (PCV) system
Engine Light ON (or Service Engine Soon Warning Light)
The Engine Control Module (ECM) monitors the volume of air consumed at idle speed. The ECM controls the Idle Air Control (IAC) motor in order to regulate the air flow through the throttle body. The amount of air flowing through the throttle body will normally determine the engine speed. If there is an Intake Air (IA) leak or a malfunction in the Positive Crankcase Ventilation (PCV) system excess air can enter the intake manifold affecting engine speed. The ECM uses sensor input in order to determine an estimated volume of air that is used during normal idle conditions. If there is any excess air, the estimated volume of air will be more than the expected value and Diagnostic Trouble Code (DTC) P2279 sets.