For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### DTC Descriptor

DTC P2279: Intake Manifold Air Leak

### Circuit/System Description

The engine control module (ECM) compares actual vacuum reading of the manifold absolute pressure (MAP) sensor at idle to a calculated vacuum reading.

### Conditions for Running the DTC

• | DTCs P0106, P0107, P0108, P0112, P0113, P0115, P0117, P0118, P0122, P0123, P0125, P0128, P0131, P0132, P0133, P0134, P0135, P0141, P0171, P0172, P0201-P0204, P0217, P0300, P0336, P0337, P0341, P0342, P0351, P0352, P0402, P0404, P0405, P0406, P0488, P0496, P0502, P2195, and P2196 are not set.

• | The evaporative emission (EVAP) purge canister commanded state is less than 100 percent.

• | The barometric pressure (BARO) is greater than 72 kPa.

• | The engine coolant temperature (ECT) is greater than 60°C (140°F).

• | The intake air temperature (IAT) sensor is greater than -20°C (-4°F).

• | The manifold absolute pressure (MAP) is less than 60 kPa.

• | The engine is operating for more than 60 seconds.

• | The engine is at idle with the throttle closed.

• | The ECM is not commanding an IAC motor reset.

• | The following components are not changing states:

- | The A/C compressor

- | The engine cooling fans

- | The automatic transmission

• | The DTC runs continuously when the above conditions are met for 5 seconds.

### Conditions for Setting the DTC

• | The ECM detects that the predicted intake air flow into the engine is not within a predetermined range of the actual air flow into the engine.

• | The condition exists for more than 20 seconds.

### Action Taken When the DTC Sets

DTC P2279 is a Type B DTC.

### Conditions for Clearing the DTC

DTC P2279 is a Type B DTC.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

• | Engine Control Module Connector End Views

• | Engine Controls Connector End Views

#### Description and Operation

Air Intake System Description

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

• | Scan Tool Data List

• | Scan Tool Data Definitions

• | Scan Tool Output Controls

### Circuit/System Verification

1. Operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. DTC P2279 should not set.
2. If the vehicle passes the Circuit/System Verification Test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records List.

### Circuit/System Testing

1. Verify that none of the following conditions exist:

• | The air intake duct system for loose connecting clamps, cracks, or other damage

• | A damaged throttle body blade or shaft

• | Splits, kinks, or improper connections at the vacuum hoses

• | An exhaust gas recirculation (EGR) system leak

• | Faulty positive crankcase ventilation (PCV) system operation

• | Carbon deposits on the throttle blade--Refer to Throttle Body Inspection and Cleaning .

• | Vacuum leaks at the intake manifold, throttle body, and injector O-rings

2. If all conditions test normal, test the engine for proper camshaft timing. Refer to Timing Belt Replacement .

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Throttle Body Assembly Replacement

• | Air Cleaner Assembly Replacement