Engine Controls - Closed Throttle Hissing Noise

TSB SBO3-03-S003

Idle Air Control Valve (IACV) Hissing Noise (Replace the IACV)

ISSUE DATE: MAY 2003

Affected Vehicles

1999-2000 Hombre (TH) with 2.2L Engine.

Service Information

Condition:
Some owners may comment on a hiss noise at closed throttle only. This may sound similar to a belt noise or a power steering pump noise when it is cold. The noise source may be identified by using a hose or a stethoscope and listening in the Idle Air Control Valve (IACV) area. This noise is most noticeable after releasing the throttle at cold idle (1050-1200 RPM). The noise is related to the IACV pintle position, typically around 70 counts.

Possible Cause:
The condition may be caused when air moves past the shoulder of the IACV pintle. The current profile imparts a disturbance to the airflow, which propagates into the intake manifold. As a result, the manifold walls vibrate causing the noise. To identify if the noise is due to the IACV, connect a Tech 2 to a warm engine and adjust the idle from 1050 RPM to 1200 RPM. The noise will be revealed if the IACV pintle is of the old design.

Correction:
Replace the IACV with P/N 8-12482-707-0.

Service Procedure

Refer to the Engine Controls sub-section of Engine in the appropriate Service Manual for IACV replacement.





Parts Information

Warranty Claim Information





Use the labor operations shown.

Labor Time includes administrative time allowance.





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