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 InformationIf 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 ...
TPMS Malfunction Light
The TPMS will not function properly if one or more of the TPMS sensors are missing
or inoperable. When the system detects a malfunction, the low tire warning light
flashes for about one minute and then stays on for the remainder of the ignition
cycle. The malfunction light comes on at each ign ...
Hill and Mountain Roads
Driving on steep hills or through mountains is different than driving on flat
or rolling terrain. Tips for driving in these conditions include:
Keep the vehicle serviced and in good shape.
Check all fluid levels and brakes, tires, cooling system, and transmission.
Shift to a lower gear whe ...