Idle Air Control Valve - Hissing Noise

File In Section: 06 - Engine/Propulsion System

Bulletin No.: 00-06-04-053

Date: December, 2000

TECHNICAL

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

Models:
1999-2000 Chevrolet Cavalier
1999-2000 Pontiac Sunfire
1999-2000 Chevrolet and GMC S/T Models (510, Sonoma)
with 2.2 L Engine (VINs 4, 5 - RPOS LN2, L43)

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 (105-1200 RPM). The noise is related to the IACV pintle position, typically around 50 counts for cars and 70 counts for trucks.

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 12482707. Refer to the Engine Controls sub-section of Engine in the appropriate Service Manual for IACV replacement.

Parts Information

Part Number Description Qty

12482707 Idle Air Control Valve 1

Parts are currently available from GMSPO.

Warranty Information

For vehicles repaired under warranty, use:

Labor
Operation Description Labor Time
Use
Valve, Idle Air Published
J5542 Control - Replace Labor Time