Radio Whine When Using The OnStar - keywords bracket chafe connector digital ground handsfree harness noise OnStar radio reception short speaker static upgrade VCIM wire

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Some customers may report that they are hearing a whistle or whine noise only when using any mode of the OnStar® system (OnStar®, Emergency or handsfree calling). This may occur with or without the engine running. The whine noise does change in intensity with engine RPM.

It is possible that the OnStar® audio harness between the VCIM and Radio may be chaffed approximately 14 inches from the radio. There will be a dash mounting bracket in this location. The harness tends to rub against the bracket and cause this condition. Remove the tape from the harness in this location and check for damage specifically on circuit 372 (black with white strip). The tape itself may not show any evidence of chaffing. Often the condition can be duplicate simply by moving the OnStar® audio harness.

Repair the wiring as needed and retest. If the concern is not resolved, resume normal diagnosis.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.