Service VME - OnStar Antenna Mast Rattle - keywords cellular noise roof

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

If a customer complains of a rattle above the driver’s head at highway speeds, one possible cause can be the OnStar antenna mast. This can be confirmed by removing just the mast portion of the antenna assembly to see if the noise disappears. To correct this condition, bend the mast to slightly impart a kink in the metal core wire. If this does not correct the condition, replace the antenna mast.

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.