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 gas) into the intake manifold so that it is drawn into the engine and burned, thus reducing HC. Estimate the amount of air inflowing from the PCV valve from the deviation between the inflow air amount of the intake manifold calculated from the manifold absolute pressure (MAP) sensor and the amount of air passing through throttle body measured using mass airflow (MAF) sensor. When the PCV hose is disengaged, the amount of air flowing from the PCV valve increases and the deviation also increases. The estimated air quantity of PCV is compared with the judgment value (upper limit value), and when it exceeds the 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 | 22 seconds or more |
| DTC Type | Two drive cycles, MIL on |
Enable Conditions
| Condition | Minimum | Maximum |
|---|---|---|
| Elapsed time after starting the engine | 15 seconds | - |
| Engine speed [ Engine Speed ] | 620 RPM | 860 RPM |
| Engine coolant temperature [ ECT Sensor 1 ] | 155.9 deg.F (68.8 deg.C) | - |
| Intake air temperature [ IAT Sensor (1) ] | 19.4 deg.F (-7.0 deg.C) | - |
| MAP value [ MAP Sensor (Hi Res) ] | - | 83 kPa (630 mmHg, 24.8 inHg) |
| 12 volt battery voltage [ Battery ] | 10.5 V | - |
| Fuel trim | 0.75 | 1.47 |
| Throttle position change amount | - | 0 deg. |
| Fuel feedback | Closed loop | |
| [ ] : HDS Parameter | ||
Malfunction Threshold
The estimated volume of intake air is 106.0 L/min (112.1 US qt/min, 93.3 lmp qt/min) - 3276.7 L/min (3462.4 US qt/min, 2883.1 lmp qt/min) or more*.
Possible Cause
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
Confirmation Procedure
Operating Condition
- Start the engine. Hold the engine speed [ Engine Speed ] at 3000 RPM without load (in P or N) until the radiator fan comes on.
- Let the engine idle for at least 22 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.