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:
Safety Chains
Always attach chains between the
vehicle and the trailer. Cross the
safety chains under the tongue
of the trailer to help prevent the
tongue from contacting the road if it
becomes separated ...
Interior Quality & Comfort
The CTS' cabin quality has held up well since this generation first hit the
road as a 2008 model, and it's still competitive against newer entrants like the
535i and M37. Among the highlights are ...
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 d ...