DTC P2279
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
| Execution | Once per driving cycle |
| Sequence | None |
| Duration | 5.5 seconds or more |
| DTC Type | Two drive cycles, MIL on |
Enable Conditions
| Condition | Minimum | Maximum | |
|---|---|---|---|
| Elapsed time after starting the engine | 15 seconds | - | |
| Engine coolant temperature [ECT Sensor 1] | 156 deg.F (69 deg.C) | - | |
| Intake air temperature [IAT Sensor] | 19 deg.F (-7 deg.C) | - | |
| MAP value [MAP Sensor Voltage] | 1, 100 RPM | - | -26 kPa (-7.8 inHg, -200 mmHg) |
| 3, 000 RPM | - | -26 kPa (-7.8 inHg, -200 mmHg) | |
| Battery voltage [Battery] | 10.5 V | - | |
| Fuel feedback | Closed loop | ||
| Other | At idle | ||
[ ]: HDS Parameter
Malfunction Threshold
The estimated volume of intake air is 150 L/min (158.5 US qt/min, 132 lmp qt/min) or more.*
*: Depends on engine speed and load
Possible Cause
- Vacuum hose fall
- Throttle body air leak
- Intake manifold air leak
- Evaporative emission (EVAP) canister purge valve failure
- Valve timing incorrect
Confirmation Procedure
Operating Condition
- Enter the maintenance mode, then 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.
- Let the engine idle for at least 5.5 seconds.
With the HDS
None.
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, the freeze data, and the on-board snapshot 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, the freeze data, and the on-board snapshot can be cleared with the scan tool Clear command or by disconnecting the 12 volt battery.