Advanced Diagnostics

Advanced Diagnostics - DTC P2279: Intake Air System Leak











General Description
The positive crankcase ventilation (PCV) system reduces hydrocarbon (HC) emissions. The PCV system recirculates unburned air/fuel mixture (blow-by vapor) into the intake manifold so that it is drawn into the engine and burned, thus reducing HC. If the PCV hose comes off at idle with the throttle closed, the amount of air supplied to the engine is considerably more than the amount of air the idle control system supplies. The powertrain control module (PCM) estimates the amount of air supplied to the engine while the throttle valve is fully closed, and if the estimated amount is more than the upper limit, it detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type, OBD Status






Enable Conditions






Malfunction Threshold
Either of these conditions is met:
- The estimated volume of intake air is 200 L/min (212 US qt/min, 176 Imp qt/min) or more when the MAP value is 35 kPa (10.2 inHg, 260 mmHg).
- The estimated volume of intake air is 200 L/min (212 US qt/min, 176 Imp qt/min) or more when the MAP value is 48 kPa (14.2 inHg, 360 mmHg).

Driving Pattern
1. Start the engine. Hold the engine speed at 3,000 rpm without load (in P or N) until the radiator fan comes on.
2. Let the engine idle for at least 22 seconds.

Diagnosis Details

Conditions for setting the DTC
When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the PCM memory. If the malfunction returns in the next (second) drive cycle, the MIL comes on and a Confirmed DTC and the freeze data are stored.

Conditions for clearing the DTC
The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the battery.