GMC 2007 Acadia Owner's Manual page 228

Did you just drive through a deep puddle
of water?
If so, your vehicle's electrical system might be
wet. The condition is usually corrected when
the electrical system dries out. A few driving trips
should turn the light off.
Have you recently changed brands of fuel?
If so, be sure to fuel your vehicle with quality fuel.
See Gasoline Octane on page 388. Poor fuel
quality causes the engine not to run as efficiently
as designed. You might notice this as stalling
after start-up, stalling when you put the vehicle
into gear, misfiring, hesitation on acceleration,
or stumbling on acceleration — these conditions
might go away once the engine is warmed up.
This will be detected by the system and cause
the light to turn on.
If you experience one or more of these conditions,
change the fuel brand you use. It will require at
least one full tank of the proper fuel to turn the
light off.
If none of the above steps have made the light
turn off, your dealer/retailer can check the vehicle.
Your dealer/retailer has the proper test equipment
and diagnostic tools to fix any mechanical or
electrical problems that might have developed.
228
Emissions Inspection and
Maintenance Programs
Some state/provincial and local governments have
or might begin programs to inspect the emission
control equipment on your vehicle. Failure to pass
this inspection could prevent you from getting a
vehicle registration.
Here are some things you need to know to help
your vehicle pass an inspection:
Your vehicle will not pass this inspection if the
check engine light is on or not working properly.
Your vehicle will not pass this inspection if
the OBD (on-board diagnostic) system determines
that critical emission control systems have not
been completely diagnosed by the system.
The vehicle would be considered not ready for
inspection. This can happen if you have recently
replaced the battery or if the battery has run
down. The diagnostic system is designed
to evaluate critical emission control systems
during normal driving. This can take several days
of routine driving. If you have done this and
your vehicle still does not pass the inspection for
lack of OBD system readiness, your dealer/retailer
can prepare the vehicle for inspection.