OnStar Vehicle Diagnostics can perform a vehicle check every month. It will check
the engine, transmission, antilock brakes, and other major vehicle systems. It also
checks the tire pressures, if the vehicle is equipped with the Tire Pressure Monitoring
System. If an On-Demand Diagnostics check is needed, press
, and an Advisor can run a check.
Connections
OnStar Additional InformationAccessories and Modifications
Adding non-dealer accessories or making modifications to the vehicle can affect
vehicle performance and safety, including such things as airbags, braking, stability,
ride and handling, emissions systems, aerodynamics, durability, and electronic systems
like antilock brakes, traction control, a ...
If No Steam Is Coming from the Engine Compartment
If an engine overheat warning is displayed but no steam can be seen or heard,
the problem may not be too serious. Sometimes the engine can get a little too hot
when the vehicle:
Climbs a long hill on a hot day.
Stops after high-speed driving.
Idles for long periods in traffic.
If the ...
When It Is Time for New Tires
Factors such as maintenance, temperatures, driving speeds, vehicle loading, and
road conditions affect the wear rate of the tires.
Treadwear indicators are one way to tell when it is time for new tires.
Treadwear indicators appear when the tires have only 1.6mm (1/16 in) or less
of tread r ...