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 vehicle is equipped with the Tire Pressure Monitoring System.
If a diagnostics check is needed between e-mails, push 
, and an Advisor can run a check.
See also:
Headlamp High/Low-Beam Changer
Headlamp High/Low-Beam Changer: Push the turn signal/lane change lever away from you to turn the high beams on.
Pull the lever toward you to return to low beams
This indicator light turns on in t ...
High-Beam On Light
The high-beam on light comes on when the high-beam headlamps are in use.
See Headlamp High/Low-Beam Changer on page 6‑2 for more information. ...
Checking Coolant
The vehicle must be on a level surface when checking the coolant level.
Check to see if coolant is visible in the coolant recovery tank. If the coolant inside the coolant recovery tank is boiling, do ...