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 vehicle is equipped with the Tire Pressure Monitoring System.

If a diagnostics check is needed between e-mails, push , and an" width=19 height=17 id="_x0000_i1807" src="images/books/1183/10/index.2.gif" border=0>, and an Advisor can run a check.