Recommended Fuel
Use regular unleaded gasoline with a posted octane rating of 87 or higher. If the octane rating is less than 87, an audible knocking noise, commonly referred to as spark knock, might be heard when driving.
If this occurs, use a gasoline rated at 87 octane or higher as soon as possible. If heavy knocking is heard when using gasoline rated at 87 octane or higher, the engine needs service.
See also:
Engine & Transmission
The CTS comes standard with a 3.0-liter V-6 engine, but our test car's
optional 3.6-liter V-6 and six-speed automatic transmission are a special pair
among drivetrains. The transmission's shifts a ...
Oil Life Remaining
If the vehicle has this display,
it shows the estimated oil life
remaining. If you see 99% Oil Life
Remaining on the display, that
means that 99% of the current oil
life remains.
When the o ...
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 ...