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 greater 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 greater 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

Component 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

Control Module References for scan tool information

### Circuit/System Verification

1. Engine running, observe the DTC information with a scan tool. DTC P2279 should not set.
2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

### Circuit/System Testing

1. Verify 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