See also:

Engine Speed Limiter
This feature prevents the engine speed from reaching an unsafe level. If the level is too high, the throttle closes or limits the fuel supply until the engine speed returns to a safe level. ...

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 v ...

How to Check Automatic Transmission Fluid
Notice: Too much or too little fluid can damage the transmission. Too much can mean that some of the fluid could come out and fall on hot engine parts or exhaust system parts, starting a fire. Too ...