Page 160 of 544

Black plate (22,1)GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
5853626) - 2014 - 3rd crc - 6/6/14
5-22 Instruments and Controls
Malfunction
Indicator Lamp
A computer system called OBD II
(On-Board Diagnostics-Second
Generation) monitors the operation
of the vehicle to ensure emissions
are at acceptable levels, helping to
maintain a clean environment. The
malfunction indicator lamp comes
on when the vehicle is placed in
ON/RUN, as a check to show it is
working. If it does not, have the
vehicle serviced by your dealer. See
Ignition Positions on page 9-24.
If the malfunction indicator lamp
comes on while the engine is
running, this indicates that the OBD
II system has detected a problem
and diagnosis and service might be
required.Malfunctions often are indicated by
the system before any problem is
apparent. Being aware of the light
can prevent more serious damage
to the vehicle. This system also
assists the service technician in
correctly diagnosing any
malfunction.
{Caution
If the vehicle is continually driven
with this light on, the emission
controls might not work as well,
the vehicle fuel economy might
not be as good, and the engine
might not run as smoothly. This
could lead to costly repairs that
might not be covered by the
vehicle warranty.
{Caution
Modifications made to the engine,
transmission, exhaust, intake,
or fuel system of the vehicle or
the replacement of the original
tires with other than those of the
same Tire Performance Criteria
(TPC) can affect the vehicle's
emission controls and can cause
this light to come on.
Modifications to these systems
could lead to costly repairs not
covered by the vehicle warranty.
This could also result in a failure
to pass a required Emission
Inspection/Maintenance test. See
Accessories and Modifications on
page 10-3.
Page 410 of 544

Black plate (36,1)GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
5853626) - 2014 - 3rd crc - 6/6/14
10-36 Vehicle Care
Air Intake:
.Removal of the air cleaner
silencer.
.Modification of the air cleaner.
Exhaust:
.Removal of the muffler and/or
resonator.
.Removal of the exhaust pipes
and exhaust pipe clamps.
Starter Switch Check
{Warning
When you are doing this
inspection, the vehicle could
move suddenly. If the vehicle
moves, you or others could be
injured.
1. Before starting this check, be sure there is enough room
around the vehicle. 2. Apply both the parking brake
and the regular brake.
Do not use the accelerator
pedal, and be ready to turn off
the engine immediately if it
starts.
3. Try to start the engine in each gear. The vehicle should start
only in P (Park) or N (Neutral).
If the vehicle starts in any other
position, contact your dealer for
service.
Automatic Transmission
Shift Lock Control
Function Check
{Warning
When you are doing this
inspection, the vehicle could
move suddenly. If the vehicle
moves, you or others could be
injured. 1. Before starting this check, be
sure there is enough room
around the vehicle. It should be
parked on a level surface.
2. Apply the parking brake. Be ready to apply the regular brake
immediately if the vehicle begins
to move.
3. With the engine off, turn the ignition on, but do not start the
engine. Without applying the
regular brake, try to move the
shift lever out of P (Park) with
normal effort. If the shift lever
moves out of P (Park), contact
your dealer for service.
Page 473 of 544

Black plate (99,1)GMC Sierra Owner Manual (GMNA-Localizing-U.S./Canada/Mexico-
5853626) - 2014 - 3rd crc - 6/6/14
Vehicle Care 10-99
.Solvents, alcohols, fuels,
or other harsh cleaners.
.Ice scrapers or other hard items.
.Aftermarket appearance caps or
covers while the lamps are
illuminated, due to excessive
heat generated.
{Caution
Failure to clean lamps properly
can cause damage to the lamp
cover that would not be covered
by the vehicle warranty.
{Caution
Using wax on low gloss black
finish stripes can increase the
gloss level and create a
non-uniform finish. Clean low
gloss stripes with soap and
water only.
Air Intakes
Clear debris from the air intakes,
between the hood and windshield,
when washing the vehicle.
Windshield and Wiper Blades
Clean the outside of the windshield
with glass cleaner.
Clean rubber blades using a lint-free
cloth or paper towel soaked with
windshield washer fluid or a mild
detergent. Wash the windshield
thoroughly when cleaning the
blades. Bugs, road grime, sap, and
a buildup of vehicle wash/wax
treatments may cause wiper
streaking.
Replace the wiper blades if they are
worn or damaged. Damage can be
caused by extreme dusty
conditions, sand, salt, heat, sun,
snow, and ice.
Weatherstrips
Apply Dielectric silicone grease on
weatherstrips to make them last
longer, seal better, and not stick or
squeak. Lubricate weatherstrips
once a year. Hot, dry climates may
require more frequent application.
Black marks from rubber material on
painted surfaces can be removed by
rubbing with a clean cloth. See
Recommended Fluids and
Lubricants on page 11-12.
Tires
Use a stiff brush with tire cleaner to
clean the tires.
{Caution
Using petroleum-based tire
dressing products on the vehicle
may damage the paint finish and/
or tires. When applying a tire
dressing, always wipe off any
overspray from all painted
surfaces on the vehicle.