HU - Test

HU: Intake Air System

HU: Introduction HU - Introduction



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HU1 CHECK FOR DIAGNOSTIC TROUBLE CODES (DTCS)

Is DTC P2279 present?

YES
GO to HU2.

NO
For all other DTCs, REFER to Diagnostic Trouble Code (DTC) Charts and Descriptions Diagnostic Trouble Code Descriptions.

For all other symptoms, GO to HU2.


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HU2 CHECK THE INTAKE AIR SYSTEM FOR LEAKS, OBSTRUCTIONS, AND DAMAGE

- Listen for vacuum leaks from the following:

- loose connections on the intake air tube at the air cleaner housing or throttle body
- cracked or punctured intake air tube.
- worn gaskets between the mass air flow (MAF) sensor and the air cleaner assembly
- vacuum supply connectors and hose
- intake manifold assembly or gasket
- exhaust gas recirculation (EGR) valve gasket leak to intake manifold
- verify the integrity of the positive crankcase ventilation (PCV) system and the proper PCV valve part number
- improperly seated engine oil dipstick, tube or oil fill cap
- aftermarket accessories and performance modifications

Are any concerns present?

YES
REPAIR as necessary.

CLEAR the DTCs. REPEAT the self-test.

NO
GO to HU3.


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HU3 CHECK THE THROTTLE BODY FOR EXCESSIVE WEAR

- Key in OFF position.
- Remove the throttle body assembly. REFER to Fuel Charging and Controls.
- Inspect the throttle body for:

- excessive wear or grooving in the throttle bore
- misaligned or worn throttle plate
- excessive gap between the throttle bore and plate

Are any concerns present?

YES
INSTALL a new throttle body assembly.

REFER to Fuel Charging and Controls.

CLEAR the DTCs. REPEAT the self-test.

NO
RETURN to Symptom Charts Symptom Related Diagnostic Procedures for further direction.