See also:

Noise Control System
The following information relates to compliance with federal noise emission standards for vehicles with a Gross Vehicle Weight Rating (GVWR) of more than 4 536 kg (10,000 lbs). The noise control syste ...

Diagnostics
OnStar Vehicle Diagnostics will perform a vehicle check every month. It will check the engine, transmission, antilock brakes, and major vehicle systems. It also checks the tire pressures, if the vehic ...

Muting a Call
During a call, all sounds from inside the vehicle can be muted so that the person on the other end of the call cannot hear them. • To mute a call, press , and then say “Mute call.” . To cancel ...