GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
56 Keys, Doors, and Windows Automatic Reversal System The sunroof has an automatic
reversal system that is only active
when the sunroof is operated in
express-close mode.
If an object is in the path while
express closing, the reversal system
will detect an object, stop, and open
the sunroof again.
If frost or other conditions prevent
closing, override the feature by
closing the sunroof in manual
mode. To stop movement, release
the switch.
Dirt and debris may collect on the
sunroof seal or in the track. This
could cause an issue with sunroof
operation or noise. It could also plug the water drainage system.
Periodically open the sunroof and
remove any obstacles or loose
debris. Wipe the sunroof seal and
roof sealing area using a clean
cloth, mild soap, and water. Do not
remove grease from the sunroof
tracks.
If water is seen dripping into the
water drainage system, this is
normal. 
GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Service and Maintenance 449.
Check tire inflation pressures.
See Tire Pressure 0 397 .
.
Inspect tire wear. See Tire
Inspection 0 404 .
.
Visually check for fluid leaks.
.
Inspect engine air cleaner filter.
See Engine Air Cleaner/Filter
0 358 .
.
Inspect brake system. See
Exterior Care 0 435 .
.
Visually inspect steering,
suspension, and chassis
components for damaged, loose,
or missing parts or signs of wear
at least once a year. See
Exterior Care 0 435 . Lubricate
the suspension and steering
components at least every other
oil change. (If equipped with
grease fittings)
.
Check restraint system
components. See Safety System
Check 0 75 . .
Visually inspect fuel system for
damage or leaks.
.
Visually inspect exhaust system
and nearby heat shields for
loose or damaged parts.
.
Lubricate body components. See
Exterior Care 0 435 .
.
Check starter switch. See Starter
Switch Check 0 374 .
.
Check automatic transmission
shift lock control function. See
Automatic Transmission Shift
Lock Control Function Check
0 374 .
.
Check ignition transmission lock.
See Ignition Transmission Lock
Check 0 374 .
.
Check parking brake and
automatic transmission park
mechanism. See Park Brake and
P (Park) Mechanism Check
0 375 . .
Check accelerator pedal for
damage, high effort, or binding.
Replace if needed.
.
Visually inspect gas strut for
signs of wear, cracks, or other
damage. Check the hold open
ability of the strut. If the hold
open ability is low, service the
gas strut. See Gas Strut(s)
0 376 .
.
Inspect sunroof track and seal,
if equipped. See Sunroof 0 55 .
.
Verify spare tire key lock
operation and lubricate as
needed. See Tire Changing
0 415 .