
GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
184 Driving and Operating
Recommended Fuel (L86 6.2LV8 Engine) . . . . . . . . . . . . . . . . . . 254
Prohibited Fuels . . . . . . . . . . . . . . 255
Fuels in Foreign Countries . . . 255
Fuel Additives . . . . . . . . . . . . . . . . 255
E85 or FlexFuel . . . . . . . . . . . . . . 255
Filling the Tank . . . . . . . . . . . . . . . 256
Filling a Portable Fuel Container . . . . . . . . . . . . . . . . . . . 258
Trailer Towing
General TowingInformation . . . . . . . . . . . . . . . . . . 259
Driving Characteristics and Towing Tips . . . . . . . . . . . . . . . . . 259
Trailer Towing . . . . . . . . . . . . . . . . 264
Towing Equipment . . . . . . . . . . . . 270
Trailer Sway Control (TSC) . . . 278
Conversions and Add-Ons
Add-On Electrical Equipment . . . . . . . . . . . . . . . . . . 280
Driving Information
Driving for Better Fuel
Economy
Driving habits can affect fuel
mileage. Here are some driving tips
to get the best fuel economy
possible:
. Set the climate controls to the
desired temperature after the
engine is started, or turn them
off when not required.
. Avoid fast starts and accelerate
smoothly.
. Brake gradually and avoid
abrupt stops.
. Avoid idling the engine for long
periods of time.
. When road and weather
conditions are appropriate, use
cruise control.
. Always follow posted speed
limits or drive more slowly when
conditions require.
. Keep vehicle tires properly
inflated. .
Combine several trips into a
single trip.
. Replace the vehicle's tires with
the same TPC Spec number
molded into the tire's sidewall
near the size.
. Follow recommended scheduled
maintenance.
Distracted Driving
Distraction comes in many forms
and can take your focus from the
task of driving. Exercise good
judgment and do not let other
activities divert your attention away
from the road. Many local
governments have enacted laws
regarding driver distraction. Become
familiar with the local laws in
your area.
To avoid distracted driving, keep
your eyes on the road, keep your
hands on the steering wheel, and
focus your attention on driving.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
Driving and Operating 255
Do not use any fuel labeled E85 or
FlexFuel. Do not use gasoline with
ethanol levels greater than 15% by
volume.
Prohibited Fuels
Caution
Do not use fuels with any of the
following conditions; doing so
may damage the vehicle and void
its warranty:. For vehicles that are not
FlexFuel, fuel labeled
greater than 15% ethanol by
volume, such as mid-level
ethanol blends (16–50%
ethanol), E85, or FlexFuel.
. Fuel with any amount of
methanol, methylal,
ferrocene, and aniline.
These fuels can corrode
metal fuel system parts or
damage plastic and rubber
parts.
(Continued)
Caution (Continued)
.Fuel containing metals such
as methylcyclopentadienyl
manganese tricarbonyl
(MMT), which can damage
the emissions control
system and spark plugs.
. Fuel with a posted octane
rating of less than the
recommended fuel. Using
this fuel will lower fuel
economy and performance,
and may decrease the life of
the emissions catalyst.
Fuels in Foreign
Countries
The U.S., Canada, and Mexico post
fuel octane ratings in anti-knock
index (AKI). For fuel not to use in a
foreign country, see Prohibited
Fuels 0255.
Fuel Additives
TOP TIER Detergent Gasoline is
highly recommended for use with
your vehicle. If your country does
not have TOP TIER Detergent
Gasoline, add ACDelco Fuel
System Treatment Plus−Gasoline to
the vehicle’ s gasoline fuel tank at
every oil change or 15 000 km
(9,000 mi), whichever occurs first.
TOP TIER Detergent Gasoline and
ACDelco Fuel System Treatment
Plus−Gasoline will help keep your
vehicle’s engine fuel deposit free
and performing optimally.
E85 or FlexFuel
Vehicles with a yellow fuel sticker
on the fuel door can use either
unleaded gasoline or fuel containing
up to 85% ethanol (E85). All other
vehicles should use only the
unleaded gasoline as described in
Recommended Fuel (L83 5.3L
V8 Engine) 0254 or
Recommended Fuel (L86 6.2L
V8 Engine) 0254.

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-13566587) - 2020 - CRC - 4/15/19
256 Driving and Operating
The use of E85 or FlexFuel is
encouraged when the vehicle is
designed to use it. E85 or FlexFuel
is made from renewable sources.
To help locate fuel stations that
carry E85 or FlexFuel, the U.S.
Department of Energy has an
alternative fuel website. See
www.afdc.energy.gov/afdc/locator/
stations.
E85 or FlexFuel should meet ASTM
Specification D 5798 or CAN/
CGSB–3.512 in Canada. Do not use
the fuel if the ethanol content is
greater than 85%. Fuel mixtures that
do not meet ASTM or CGSB
specifications can affect driveability
and could cause the malfunction
indicator lamp to come on.
The starting characteristics of E85
or FlexFuel make it unsuitable for
use when temperatures fall below
−18 °C (0 °F). Use gasoline or add
gasoline to the E85 or FlexFuel.Because E85 or FlexFuel has less
energy per liter (gallon) than
gasoline, the vehicle will need to be
refilled more often. See
Filling the
Tank 0256.
The only GM approved aftermarket
additive is ACDelco Fuel System
Treatment Plus-FlexFuel. Follow the
instructions on the bottle for proper
use. This product is available at
your GM dealer.
Caution
Some additives are not
compatible with E85 or FlexFuel
and can harm the vehicle's fuel
system. Use only additives
approved by GM for E85 or
FlexFuel vehicles. Damage
caused by unapproved additives
would not be covered by the
vehicle warranty.
Caution
Do not use fuel containing
methanol. It can corrode metal
parts in the fuel system and also
damage plastic and rubber parts.
That damage would not be
covered under the vehicle
warranty.
To help keep the engine running
efficiently, fill the tank with gasoline,
up to E15, after filling the tank with
E85 one or two times.
Filling the Tank
An arrow on the fuel gauge
indicates which side of the vehicle
the fuel door is on. See Fuel Gauge
0 130.
{Warning
Fuel vapors and fuel fires burn
violently and can cause injury or
death.
(Continued)

GMC Yukon/Yukon XL/Denali Owner Manual (GMNA-Localizing-U.S./Cana-
da/Mexico-13566587) - 2020 - CRC - 4/15/19
Index 425
Fluid (cont'd)Four-Wheel Drive
Transfer Case . . . . . . . . . . . . . . . 219
Washer . . . . . . . . . . . . . . . . . . . . . . . 302
Fog Lamps . . . . . . . . . . . . . . . . . . . . . 169 Bulb Replacement . . . . . . . . . . . . 312
Folding Mirrors . . . . . . . . . . . . . . . . . . 38
Forward Collision Alert (FCA) System . . . . . . . . . . . . . . . . . 245
Four-Wheel Drive . . . . . . . . . . 219, 305
Four-Wheel-Drive Light . . . . . . . . . 139
Frequency Statement Radio . . . . . . . . . . . . . . . . . . . . . . . . . 405
Front Axle . . . . . . . . . . . . . . . . . . . . . . 306
Front Fog Lamp
Light . . . . . . . . . . . . . . . . . . . . . . . . . . 143
Front Seats Heated and Ventilated . . . . . . . . . . 54
Fuel Additives . . . . . . . . . . . . . . . . . . . . . 255
Economy, Driving for Better . . . 184
Filling a Portable FuelContainer . . . . . . . . . . . . . . . . . . . 258
Filling the Tank . . . . . . . . . . . . . . . 256
Foreign Countries . . . . . . . . . . . . 255
Gauge . . . . . . . . . . . . . . . . . . . . . . . . 130
Low Fuel Warning Light . . . . . . . 142
Management, Active . . . . . . . . . . .211 Fuel (cont'd)
Prohibited Fuels . . . . . . . . . . . . . . 255
Recommended . . . . . . . . . . . . . . . 254
Top Tier . . . . . . . . . . . . . . . . . . . . . . 254
Full-Size Spare Tire . . . . . . . . . . . . 359
Fuses Engine Compartment FuseBlock . . . . . . . . . . . . . . . . . . . . . . . . 315
Fuses and Circuit Breakers . . . 315
Instrument Panel Fuse
Block . . . . . . . . . . . . . . . . . . . 320, 323
Rear Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . 325
G
Garage Door Opener . . . . . . . . . . . 160Programming . . . . . . . . . . . . . . . . . 160
Gas Strut(s) . . . . . . . . . . . . . . . . . . . . 310
Gauges Engine CoolantTemperature . . . . . . . . . . . . . . . . 131
Engine Oil Pressure . . . . . . . . . . 130
Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . 130
Odometer . . . . . . . . . . . . . . . . . . . . . 129
Speedometer . . . . . . . . . . . . . . . . . 129
Tachometer . . . . . . . . . . . . . . . . . . . 129
Transmission Temperature . . . . 132
Trip Odometer . . . . . . . . . . . . . . . . 129 Gauges (cont'd)
Voltmeter . . . . . . . . . . . . . . . . . . . . . 133
Warning Lights and
Indicators . . . . . . . . . . . . . . . . . . . 125
General Information Service and Maintenance . . . . . 377
Towing . . . . . . . . . . . . . . . . . . . . . . . . 259
Vehicle Care . . . . . . . . . . . . . . . . . . 282
Glass Replacement . . . . . . . . . . . . . 310
Glove Box . . . . . . . . . . . . . . . . . . . . . . 109
GM Mobility Reimbursement
Program . . . . . . . . . . . . . . . . . . . . . . . 399
H
Hazard Warning Flashers . . . . . . . 168
Head Restraints . . . . . . . . . . . . . . . . . 47
Head-up Display . . . . . . . . . . . . . . . . 147
HeadlampsAiming . . . . . . . . . . . . . . . . . . . . . . . . 312
Automatic . . . . . . . . . . . . . . . . . . . . . 167
Bulb Replacement . . . . . . . . . . . . 312
Daytime Running
Lamps (DRL) . . . . . . . . . . . . . . . . 167
Flash-to-Pass . . . . . . . . . . . . . . . . . 167
High Intensity Discharge
(HID) Lighting . . . . . . . . . . . . . . . 312
High-Beam On Light . . . . . . . . . . 143
High/Low Beam Changer . . . . . 166