GMC 2007 Envoy - Manual (Page 216)

Service Four-Wheel Drive
Warning Light
This light should come
on briefly when you turn
on the ignition, as a
check to show you
it is working.
The service four-wheel drive light comes on to
indicate that there may be a problem with the drive
system and service is required. Malfunctions
can be indicated by the system before any problem
is apparent, which may prevent serious damage
to the vehicle. This system is also designed
to assist your dealer in correctly diagnosing a
malfunction.
Check Gages Warning Light
The check gages light
will come on briefly
when you are starting
the engine.
If the light comes on and stays on while you are
driving, check your coolant temperature and
engine oil pressure gages to see if they are in the
warning zones.
Gate Ajar Light
If this light comes on,
the liftgate or liftglass is
not completely shut.
Close the liftgate or liftglass. Never drive with the
liftgate or liftglass even partially open.
216