2018 GMC YUKON XL check engine

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
298 Vehicle Care Checking Brake Fluid
With the vehicle in P (Park) on a
level surface, the brake fluid level
should be between the minimum
and maximum marks on the brake
fluid reservoir.
There are only two reasons why the
brake fluid level in the reservoir may
go down:
.
Normal brake lining wear. When
new linings are installed, the
fluid level goes back up.
.
A fluid leak in the brake
hydraulic system. Have the
brake hydraulic system fixed.
With a leak, the brakes will not
work well.
Always clean the brake fluid
reservoir cap and the area around
the cap before removing it.
Do not top off the brake fluid.
Adding fluid does not correct a leak.
If fluid is added when the linings are
worn, there will be too much fluid
when new brake linings are
installed. Add or remove fluid, as
necessary, only when work is done
on the brake hydraulic system. { WarningIf too much brake fluid is added, it
can spill on the engine and burn,
if the engine is hot enough. You
or others could be burned, and
the vehicle could be damaged.
Add brake fluid only when work is
done on the brake hydraulic
system.
When the brake fluid falls to a low
level, the brake warning light comes
on. See Brake System Warning
Light 0 145 .
Brake fluid absorbs water over time
which degrades the effectiveness of
the brake fluid. Replace brake fluid
at the specified intervals to prevent
increased stopping distance. See
Maintenance Schedule 0 370 .
What to Add
Use only GM approved DOT 3
brake fluid from a clean, sealed
container. See Recommended
Fluids and Lubricants 0 379 .{ WarningThe wrong or contaminated brake
fluid could result in damage to the
brake system. This could result in
the loss of braking leading to a
possible injury. Always use the
proper GM approved brake fluid.
CautionIf brake fluid is spilled on the
vehicle's painted surfaces, the
paint finish can be damaged.
Immediately wash off any painted
surface.
Battery - North America The original equipment battery is
maintenance free. Do not remove
the cap and do not add fluid.
Refer to the replacement number
shown on the original battery label
when a new battery is needed. See
Engine Compartment Overview
0 280 for battery location.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
302 Vehicle Care to its sale or delivery to the
ultimate purchaser or while it is
in use; or
2. The use of the vehicle after
such device or element of
design has been removed or
rendered inoperative by any
person.
Among those acts presumed to
constitute tampering are the acts
listed below.
Insulation:
Removal of the noise shields or any
underhood insulation.
Engine:
Removal or rendering engine speed
governor, if the vehicle has one,
inoperative so as to allow engine
speed to exceed manufacturer
specifications.
Fan and Drive:
.
Removal of fan clutch, if the
vehicle has one, or rendering
clutch inoperative.
.
Removal of the fan shroud, if the
vehicle has one. 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
{ WarningWhen 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
{ WarningWhen 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.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
Vehicle Care 3032. 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.
Ignition Transmission
Lock Check If equipped with a Key Access
ignition, while parked and with the
parking brake set, try to turn the
ignition off in each shift lever
position.
.
The ignition should turn off only
when the shift lever is in
P (Park).
.
The key should come out only
when the ignition is off.
Contact your dealer if service is
required. Park Brake and P (Park)
Mechanism Check
{ WarningWhen you are doing this check,
the vehicle could begin to move.
You or others could be injured
and property could be damaged.
Make sure there is room in front
of the vehicle in case it begins to
roll. Be ready to apply the regular
brake at once should the vehicle
begin to move.
Park on a fairly steep hill, with the
vehicle facing downhill. Keeping
your foot on the regular brake, set
the parking brake.
.
To check the parking brake's
holding ability: With the engine
running and the transmission in
N (Neutral), slowly remove foot
pressure from the regular brake
pedal. Do this until the vehicle is
held by the parking brake only. .
To check the P (Park)
mechanism's holding ability:
With the engine running, shift to
P (Park). Then release the
parking brake followed by the
regular brake.
Contact your dealer if service is
required.
Wiper Blade Replacement Windshield wiper blades should be
inspected for wear or cracking.
For the proper type and size, see
Maintenance Replacement Parts
0 380 .
Front Wiper Blade
Replacement To replace the wiper blade
assembly:
1. Pull the windshield wiper
assembly away from the
windshield.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
Vehicle Care 353Caution (Continued)warranty. Whenever possible, turn
off or unplug all accessories on
either vehicle when jump starting.
3. Turn the ignition off on both
vehicles. Unplug unnecessary
accessories plugged into the
accessory power outlets. Turn
off the radio and all the lamps
that are not needed. This will
avoid sparks and help save
both batteries. And it could
save the radio!
4. Open the hood on the other
vehicle and locate the
positive (+) and negative ( − )
terminal locations on that
vehicle.
The positive (+) terminal is
under a red plastic cover at the
positive battery post. To
uncover the positive (+)
terminal, open the red plastic
cover. For more information on the
location of the remote
positive (+) and remote
negative ( − ) terminals, see
Engine Compartment Overview
0 280 .
{ WarningAn electric fan can start up even
when the engine is not running
and can injure you. Keep hands,
clothing, and tools away from any
underhood electric fan.
{ Warning
Using a match near a battery can
cause battery gas to explode.
People have been hurt doing this,
and some have been blinded.
Use a flashlight if you need more
light.
Battery fluid contains acid that
can burn you. Do not get it on
you. If you accidentally get it in
(Continued) Warning (Continued) your eyes or on your skin, flush
the place with water and get
medical help immediately.
{ WarningFans or other moving engine
parts can injure you badly. Keep
your hands away from moving
parts once the engine is running.
5. Check that the jumper cables
do not have loose or missing
insulation. If they do, you could
get a shock. The vehicles
could be damaged too.
Before you connect the cables,
here are some basic things you
should know. Positive (+) will
go to positive (+) or to a remote
positive (+) terminal if the
vehicle has one. Negative ( − )
will go to a heavy, unpainted

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
Vehicle Care 357To dinghy tow:
1. Position the vehicle being
towed behind the tow vehicle,
facing forward and on a level
surface.
2. Securely attach the vehicle
being towed to the tow vehicle.
3. Apply the parking brake and
start the engine.
4. Shift the transfer case to
N (Neutral). See “ Shifting into
N (Neutral) ” under Four-Wheel
Drive 0 222 . Check that the
vehicle is in N (Neutral) by
starting the engine and shifting
the transmission to
R (Reverse) and then to D
(Drive). There should be no
movement of the vehicle while
shifting.
5. Shift the transmission into
D (Drive). Turn the engine off. CautionFailure to disconnect the negative
battery cable or to have it contact
the terminals can cause damage
to the vehicle.
6. Disconnect the negative
battery cable at the battery and
secure the nut and bolt. Cover
the negative battery post with a
non-conductive material to
prevent any contact with the
negative battery terminal.
7. Shift the transmission to
P (Park).
Caution
If the steering column is locked,
vehicle damage may occur.
8. Move the steering wheel to
make sure the steering column
is unlocked.
9. With a foot on the brake pedal,
release the parking brake. 10. Keep the ignition key in the
towed vehicle in ACC/
ACCESSORY to prevent the
steering column from locking.
If equipped with Keyless
Access, keep the RKE
transmitter outside of the
vehicle, and manually lock the
doors. Access the vehicle as if
it has a dead RKE transmitter
battery, by using the key in the
door lock.
Disconnecting the Towed Vehicle
Before disconnecting the towed
vehicle:
1. Park on a level surface.
2. Set the parking brake, then
shift the transmission to
P (Park).
3. Connect the battery.
4. Apply the brake pedal.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
358 Vehicle Care 5. Turn the ignition to ON/RUN
with the engine off. Shift the
transfer case out of N (Neutral)
to 2
m . See “ Shifting out of
N (Neutral) ” under Four-Wheel
Drive 0 222 . See your dealer if
the transfer case cannot be
shifted out of N (Neutral).
6. Check that the vehicle is in 2
mby starting the engine and
shifting the transmission to
R (Reverse) and then to D
(Drive). There should be
movement of the vehicle while
shifting.
7. Shift the transmission to
P (Park) and turn off the
ignition.
8. Disconnect the vehicle from the
tow vehicle.
9. Release the parking brake.
10. Reset any lost presets.
The outside temperature
display will default to 0 °C
(32 °F) but will reset with
normal usage. Dolly Towing – Front Towing
(Front Wheels Off the Ground)
CautionIf a two-wheel-drive vehicle is
towed with the rear wheels on the
ground, the transmission could be
damaged. The repairs would not
be covered by the vehicle
warranty. Never tow the vehicle
with the rear wheels on the
ground. CautionTowing a four-wheel-drive vehicle
with all four wheels on the
ground, or even with only two of
its wheels on the ground, will
damage drivetrain components.
Do not tow a four-wheel-drive
vehicle with any of its wheels on
the ground.
This vehicle should not be towed
with the rear wheels on the ground.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
370 Service and Maintenance have your dealer perform these
services every 12 000 km/7,500 mi.
Proper vehicle maintenance helps to
keep the vehicle in good working
condition, improves fuel economy,
and reduces vehicle emissions.
Because of the way people use
vehicles, maintenance needs vary.
There may need to be more
frequent checks and services. The
Additional Required Services -
Normal are for vehicles that:
.
Carry passengers and cargo
within recommended limits on
the Tire and Loading Information
label. See Vehicle Load Limits
0 200 .
.
Are driven on reasonable road
surfaces within legal driving
limits.
.
Use the recommended fuel. See
Fuel 0 254 .
Refer to the information in the
Maintenance Schedule Additional
Required Services - Normal chart.
The Additional Required Services -
Severe are for vehicles that are: .
Mainly driven in heavy city traffic
in hot weather
.
Mainly driven in hilly or
mountainous terrain
.
Frequently towing a trailer
.
Used for high speed or
competitive driving
.
Used for taxi, police, or delivery
service
Refer to the information in the
Maintenance Schedule Additional
Required Services - Severe chart.
{ WarningPerforming maintenance work can
be dangerous and can cause
serious injury. Perform
maintenance work only if the
required information, proper tools,
and equipment are available.
If they are not, see your dealer to
have a trained technician do the
work. See Doing Your Own
Service Work 0 278 .Maintenance
Schedule Owner Checks and Services At Each Fuel Stop
.
Check the engine oil level. See
Engine Oil 0 283 .
Once a Month
.
Check the tire inflation
pressures. See Tire Pressure
0 327 .
.
Inspect the tires for wear. See
Tire Inspection 0 333 .
.
Check the windshield washer
fluid level. See Washer Fluid
0 296 .
Engine Oil Change When the CHANGE ENGINE OIL
SOON message displays, have the
engine oil and filter changed within
the next 1 000 km/600 mi. If driven
under the best conditions, the
engine oil life system may not
indicate the need for vehicle service
for up to a year. The engine oil and
filter must be changed at least once

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-11349262) - 2018 - crc - 6/20/17
Service and Maintenance 371a year and the oil life system must
be reset. Your trained dealer
technician can perform this work.
If the engine oil life system is reset
accidentally, service the vehicle
within 5 000 km/3,000 mi since the
last service. Reset the oil life
system when the oil is changed.
See Engine Oil Life System 0 285 .
Tire Rotation and Required
Services Every 12 000 km/
7,500 mi Rotate the tires, if recommended for
the vehicle, and perform the
following services. See Tire
Rotation 0 334 .
.
Check engine oil level and oil
life percentage. If needed,
change engine oil and filter, and
reset oil life system.
See Engine Oil 0 283 and
Engine Oil Life System 0 285 . .
Check engine coolant level. See
Cooling System 0 291 .
.
Check windshield washer fluid
level. See Washer Fluid 0 296 .
.
Visually inspect windshield wiper
blades for wear, cracking,
or contamination. See Exterior
Care 0 360 . Replace worn or
damaged wiper blades. See
Wiper Blade Replacement
0 303 .
.
Check tire inflation pressures.
See Tire Pressure 0 327 .
.
Inspect tire wear. See Tire
Inspection 0 333 .
.
Visually check for fluid leaks.
.
Inspect engine air cleaner filter.
See Engine Air Cleaner/Filter
0 290 .
.
Inspect brake system. See
Exterior Care 0 360 . .
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 0 360 . 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 83 .
.
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 0 360 .
.
Check starter switch. See Starter
Switch Check 0 302 .