P2279

DTC P2279 Intake Air System Leak

Circuit Description
The Manifold Absolute Pressure (MAP) sensor measures the changes in the intake manifold pressure which result from engine load (intake manifold vacuum) and rpm changes. The MAP sensor converts these changes into a voltage output. The engine control module (ECM) sends a 5-volt reference voltage to the MAP sensor. As the intake manifold pressure changes, the output voltage of the MAP sensor also changes. A low voltage (high vacuum) output of 1 to 2 volts is present at idle. A high voltage (low vacuum) output of 4.0 to 4.8 volts is present at wide open throttle. A large quantity of air entering the engine indicates and acceleration or high load condition while a small quantity of air indicates a deceleration or idle condition. Under idle conditions, the MAP estimate correction is a weighted difference between the predicted MAP and the actual MAP reading.

Conditions for Setting the DTC
- DTCs P0106, P0107, P0108, P0112, P0113, P0115, P0116, P0117, P0118, P0122, P0123, P0126, P0131, P0132, P0133, P0135, P0141, P0171, P0172, P0201, P0202, P0203, P0204, P0217, P0300, P0336, P0337, P0341, P0342, P0351, P0352, P0402, P0404, P0405, P0406, P0441, P0502, P1133, P1134, P1171, P1167, P1404, P1441 will not set.
- Engine run time is greater than 60 seconds.
- Barometric Pressure (BARO) is greater than 72 kPa (10.4 psi).
- Engine Coolant Temperature (ECT) is higher than 60 °C (140 °F).
- Ignition voltage is between 11 V and 16 V.
- Intake Air Temperature (IAT) is higher than -20 °C (-4 °F).
- Manifold Absolute Pressure (MAP) is less than 60 kPa (8.7 psi).
- Engine is in idle condition. (No AC transition, No AT shifting change, No coolant fan transition, No IAC reset, Crank to run c/l delay expired).
- Above conditions met for more than 5 seconds.
- MAP estimate correction is greater than the predetermined values for 20 seconds.

Action Taken When the DTC Sets
- The Malfunction Indicator Lamp (MIL) will illuminate.
- The ECM will record operating conditions at the time the diagnostic fail. This information will be stored in the Freeze Frame and Failure Records buffers.
- A history DTC is stored.

Conditions for Clearing the MIL/DTC
- The MIL will turn off at the end of three (3) consecutive validation cycles in which the diagnostic runs without a fault.
- A history DTC will clear after 40 warm up cycles without a fault.
- DTC(s) can be cleared by using the scan tool.

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