Treadwear
The treadwear grade is a comparative rating based on the wear rate of the tire when tested under controlled conditions on a specified government test course. For example, a tire graded 150 would wear one and a half (1½) times as well on the government course as a tire graded 100. The relative performance of tires depends upon the actual conditions of their use, however, and may depart significantly from the norm due to variations in driving habits, service practices and differences in road characteristics and climate.
See also:
How to Check
Use a good quality pocket-type gauge to check tire pressure. Proper tire inflation
cannot be determined by looking at the tire. Check the tire inflation pressure when
the tires are cold meaning th ...
Shifting Into Park
WARNING!
It can be dangerous to get out of
the vehicle if the shift lever is not
fully in P (Park) with the parking
brake firmly set. The vehicle can
roll. If you have left the engine
runni ...
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 ...