Impala V8-5.3L (2008)
Electronic Noise Suppressor: Customer Interest
Audio System - Noise When Using OnStar(R)
TECHNICAL
Bulletin No.: 07-08-46-002D
Date: July 29, 2009
Subject: Audio Whine Noise from Radio Speakers When Using OnStar(R) (Install Noise Suppression Filter)
Models:
2007-2010 GM Passenger Cars and Trucks (Including Saturn)
2007-2010 HUMMER H2, H3
2007-2009 Saab 9-7X
Equipped with OnStar(R) (RPO UE1)
Supercede:
This bulletin is being revised to update the Warranty Information. Please discard Corporate Bulletin Number 07-08-46-002C (Section 08 - Body and
Accessories).
Condition
Some customers may comment on an audio whine coming from the radio speakers when using the OnStar(R) system. The amplitude and frequency of the
whine will change with an increase or decrease in engine speed.
Cause
This condition may be caused by electrical noise on the OnStar(R) Vehicle Communication Interface Module (VCIM) battery feed wire being passed to
the microphone output pins at the radio.
Correction
Technicians are to install a noise suppression filter, P/N 1224205, into the OnStar(R) battery voltage circuit, a few centimeters (inches) from the VCIM.
The filter package has three attached wires - a single yellow wire at one end with a yellow wire and a black wire at the other. Install the single yellow
wire side into the battery voltage circuit towards the VCIM. Install the remaining single yellow wire into the battery voltage circuit toward the fuse and
the black wire to ground.
Important
The noise suppression filter is polarity sensitive. The filter is designed to be most effective when the end with the capacitor ground is connected
towards the source of the electrical noise. Install the filter in this polarity first. If the noise level is still not satisfactory, try disconnecting the
capacitor ground. In some cases, if the first installation does not correct the noise, try reversing the filter polarity (removing the filter, turning
it end for end and then reinstalling it) and grounding the capacitor lead.
Parts Information
Warranty Information (excluding Saab U.S. Models)
For vehicles repaired under warranty, use the table above.
