DTC Advanced Diagnostics: P2279 (KA/KC models)

DTC Advanced Diagnostics: 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	22 seconds or more
DTC Type	Two drive cycles, MIL on

Enable Conditions

Condition	Minimum	Maximum
Elapsed time after VTEC switched	3.0 seconds	–
Elapsed time after starting the engine	15 seconds	–
Engine coolant temperature [ECT SENSOR 1]	156 °F (69 °C)	–
Intake air temperature [IAT SENSOR (1)]	19 °F (-7 °C)	–
MAP value [MAP SENSOR]	–	80 kPa (23.7 inHg, 600 mmHg)
12 volt battery voltage [BATTERY]	10.5 V	–
Fuel trim	0.75	1.47
Fuel feedback	Closed loop
Other	At idle

[ ]: HDS Parameter

Malfunction Threshold

Either of these conditions is met:

	The estimated volume of intake air is 160 L/min (169.1 US qt/min, 140.8 lmp qt/min) or more when the MAP value [MAP SENSOR] is -67 kPa (-19.7 inHg, -500 mmHg).
	The estimated volume of intake air is 120 L/min (126.8 US qt/min, 105.6 lmp qt/min) or more when the MAP value [MAP SENSOR] is -53 kPa (-15.7 inHg, -400 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 misinstalled
	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

Operating Condition

1.	Start the engine. Hold the engine speed [ENGINE SPEED] at 3,000 rpm without load (CVT in P or N, M/T in neutral) until the radiator fan comes on.
2.	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 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 12 volt battery.