Advanced Diagnostics
Advanced Diagnostics - DTC P2279: Intake Air System LeakGeneral 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 236 L/min (249.4 US qt/min, 207.6 Imp qt/min) or more when the MAP value [MAP SENSOR] is 35 kPa (10.2 inHg, 260 mmHg).
- The estimated volume of intake air is 193 L/min (203.9 US qt/min, 169.7 Imp qt/min) or more when the MAP value [MAP SENSOR] is 48 kPa (14.2 inHg, 360 mmHg).
Possible Cause
NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
- Vacuum hose fall
- Throttle body air leak
- Intake manifold air leak
- Evaporative emission (EVAP) canister purge valve failure
- Valve timing incorrect
- Manifold absolute pressure (MAP) sensor range/performance problem
Confirmation Procedure
With the HDS
None.
With the Driving Pattern
1. Start the engine. Hold the engine speed [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.