GMC Sierra Denali Owner's Manual page 181

SERVICE 4WD
If a problem occurs with the four wheel drive system,
this message will appear on the DIC. If this message
appears, stop as soon as possible and turn off the
vehicle. Restart the vehicle and check for the message
on the DIC display. If the message is still displayed,
or appears again when you begin driving, the four wheel
drive system needs service.
SERVICE AIR SUSPENSION
If a problem occurs with the suspension system, this
message will appear
on
the DIC. If this message
appears, stop as soon as possible and turn off the
vehicle. Restart the vehicle and check for the message
on the DIC display. If the message is still displayed,
or appears again when you begin driving, the air
suspension system needs service.
TURN SIGNAL ON
If a turn signal is left on for 314 of a mile (1.2 km), this
message will appear on the display and you will
hear a chime. Move the turn signaVmultifunction lever to
the off position. Pressing the select button will
acknowledge this message and clear it from the DIC
display.
CARGO LAMP ON
If the cargo lamp is on, this message will appear on the
DIC and you will hear a chime. Turn off the vehicle
and check the liftgate. Restart the vehicle and check for
the message on the DIC display. Pressing the select
button will acknowledge this message and clear it from
the DIC display.
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