
Black plate (93,1)GMC Yukon/Yukon XL Owner Manual - 2011
Driving and Operating 9-93
If the disconnect occurs while
the vehicle is moving, this
message will continue until
the ignition is turned off. This
message will also turn off if
the driver acknowledges this
message off or if the trailer
harness is re-connected.
2. There is an electrical fault in the wiring to the electric trailer
brakes. This message will
continue as long as there is
an electrical fault in the trailer
wiring. This message will
also turn off if the driver
acknowledges this message off.
To determine if the electrical fault
is on the vehicle side or trailer
side of the trailer wiring harness
connection, do the following:
1. Disconnect the trailer wiring harness from the vehicle.
2. Turn the ignition OFF. 3. Wait ten seconds, then turn the
ignition back to RUN.
4. If the CHECK TRAILER WIRING message re-appears, the
electrical fault is on the
vehicle side.
If the CHECK TRAILER WIRING
message only re-appears when
connecting the trailer wiring
harness to the vehicle, the
electrical fault is on the
trailer side.
SERVICE TRAILER BRAKE
SYSTEM –This message will
be displayed when there is a
problem with the ITBC system.
If this message persists over
multiple ignition cycles there is
problem with the ITBC system.
Take the vehicle to an authorized
GM dealer to have the ITBC system
diagnosed and repaired. If either the CHECK TRAILER
WIRING or SERVICE TRAILER
BRAKE SYSTEM message is
displayed while driving the vehicle,
power is no longer available to
the trailer brakes. When traffic
conditions allow, carefully pull the
vehicle over to the side of the road
and turn the ignition off. Check the
wiring connection to the trailer and
turn the ignition back on. If either of
these messages continues, either
the vehicle or trailer needs service.
An authorized GM dealer may
be able to diagnose and repair
problems with the trailer. However,
any diagnosis and repair of the
trailer is not covered under the
vehicle warranty. Please contact
your trailer dealer for assistance
with trailer repairs and trailer
warranty information.

Black plate (23,1)GMC Yukon/Yukon XL Owner Manual - 2011
Vehicle Care 10-23
.Idles for long periods in traffic.
.Tows a trailer. SeeTrailer
Towing on page 9‑79.
If the overheat warning is displayed
with no sign of steam:
1. Turn the air conditioning off.
2. Turn the heater on to the highest temperature and to the highest
fan speed. Open the windows as
necessary.
3. In heavy traffic, let the engine idle in N (Neutral)
while stopped. If it is safe to
do so, pull off the road, shift to
P (Park) or N (Neutral) and let
the engine idle.
If the temperature overheat gauge
is no longer in the overheat zone
or an overheat warning no longer
displays, the vehicle can be driven.
Continue to drive the vehicle slowly
for about 10 minutes. Keep a safe
vehicle distance from the vehicle in
front. If the warning does not come
back on, continue to drive normally. If the warning continues, pull
over, stop, and park the vehicle
right away.
If there is no sign of steam, idle
the engine for three minutes
while parked. If the warning is still
displayed, turn off the engine until it
cools down. Also, see
“Overheated
Engine Protection Operating Mode”
later in this section.
Overheated Engine
Protection
Operating Mode
If an overheated engine condition
exists and the ENGINE POWER IS
REDUCED message is displayed,
an overheat protection mode which
alternates firing groups of cylinders
helps prevent engine damage. In
this mode, a loss in power and
engine performance will be noticed.
This operating mode allows the
vehicle to be driven to a safe place
in an emergency. Driving extended distances and/or towing a trailer
in the overheat protection mode
should be avoided.
Notice:
After driving in the
overheated engine protection
operating mode, to avoid engine
damage, allow the engine to cool
before attempting any repair.
The engine oil will be severely
degraded. Repair the cause of
coolant loss, change the oil and
reset the oil life system. See
Engine Oil on page 10‑7.
Engine Fan
If the vehicle has a clutched
engine cooling fan, when the clutch
is engaged, the fan spins faster to
provide more air to cool the engine.
In most everyday driving conditions,
the fan is spinning slower and
the clutch is not fully engaged.

Black plate (24,1)GMC Yukon/Yukon XL Owner Manual - 2011
10-24 Vehicle Care
This improves fuel economy and
reduces fan noise. Under heavy
vehicle loading, trailer towing, and/
or high outside temperatures, the
fan speed increases as the clutch
more fully engages, so an increase
in fan noise may be heard. This is
normal and should not be mistaken
as the transmission slipping or
making extra shifts. It is merely the
cooling system functioning properly.
The fan will slow down when
additional cooling is not required
and the clutch disengages.
This fan noise may also be heard
when starting the engine. It will go
away as the fan clutch partially
disengages.
If the vehicle has electric cooling
fans, the fans may be heard
spinning at low speed during most
everyday driving. The fans may
turn off if no cooling is required.
Under heavy vehicle loading, trailer
towing, high outside temperatures,or operation of the air conditioning
system, the fans may change to
high speed and an increase in fan
noise may be heard. This is
normal and indicates that the
cooling system is functioning
properly. The fans will change to
low speed when additional cooling
is no longer required.
Power Steering Fluid
If the vehicle is a hybrid, see the
hybrid supplement for more
information.
See
Engine Compartment Overview
on page 10‑6 for reservoir location.
When to Check Power Steering
Fluid
It is not necessary to regularly
check power steering fluid unless
there is a leak suspected in the
system or an unusual noise is
heard. A fluid loss in this system
could indicate a problem. Have the
system inspected and repaired.
How to Check Power Steering
Fluid
To check the power steering fluid:
1. Turn the key off and let the
engine compartment cool down.
2. Wipe the cap and the top of the reservoir clean.
3. Unscrew the cap and wipe the dipstick with a clean rag.
4. Replace the cap and completely tighten it.
5. Remove the cap again and look at the fluid level on the dipstick.

Black plate (43,1)GMC Yukon/Yukon XL Owner Manual - 2011
Vehicle Care 10-43
The vehicle may not be equipped
with all of the fuses, relays, and
features shown.Fuses Usage
1 Right Trailer
Stop/Turn Lamp
2 Electronic Stability
Suspension Control,
Automatic Level Control
Exhaust
3 Left Trailer Stop/
Turn Lamp
4 Engine Controls
5 Engine Control Module,
Throttle Control
6 Trailer Brake Controller
7 Front Washer
8 Oxygen Sensors
9 Antilock Brakes
System 2
10 Trailer Back-up Lamps Fuses Usage
11 Driver Side Low-Beam
Headlamp
12 Engine Control Module
(Battery)
13 Fuel Injectors, Ignition
Coils (Right Side)
14 Transmission Control
Module (Battery)
15 Vehicle Back-up Lamps
16 Passenger Side
Low-Beam Headlamp
17 Air Conditioning
Compressor
18 Oxygen Sensors
19 Transmission Controls
(Ignition)
20 Fuel Pump
21 Fuel System Control
Module
22 Headlamp Washer Fuses Usage
23 Rear Windshield Washer
24 Fuel Injectors, Ignition
Coils (Left Side)
25 Trailer Park Lamps
26 Driver Side Park Lamps
27 Passenger Side Park
Lamps
28 Fog Lamps
29 Horn
30 Passenger Side
High-Beam Headlamp
31 Daytime Running Lamps
(DRL) (If Equipped)
32 Driver Side High-Beam
Headlamp
33 Daytime Running
Lamps 2 (If Equipped)
34 Sunroof
35 Key Ignition System,
Theft Deterrent System

Black plate (44,1)GMC Yukon/Yukon XL Owner Manual - 2011
10-44 Vehicle Care
FusesUsage
36 Windshield Wiper
37 SEO B2 Upfitter Usage
(Battery)
38 Electric Adjustable
Pedals
39 Climate Controls
(Battery)
40 Airbag System (Ignition)
41 Amplifier
42 Audio System
43 Miscellaneous (Ignition),
Cruise Control
44 Liftgate Release
45 Airbag System (Battery)
46 Instrument Panel Cluster
47 Not Used Fuses
Usage
48 Auxiliary Climate Control
(Ignition)
49 Center High-Mounted
Stoplamp (CHMSL)
50 Rear Defogger
51 Heated Mirrors
52 SEO B1 Upfitter Usage
(Battery)
53 Cigarette Lighter,
Auxiliary Power Outlet
54 Automatic Level Control
Compressor Relay
55 Climate Controls
(Ignition)
56 Engine Control Module,
Secondary Fuel Pump
(Ignition) J-Case
Fuses Usage
57 Cooling Fan 1
58 Automatic Level Control
Compressor
59 Heavy Duty Antilock
Braking System
60 Cooling Fan 2
61 Antilock Brake System 1
62 Starter
63 Stud 2 (Trailer Brakes)
64 Left Bussed Electrical
Center 1
65 Electric Running Boards
66 Heated Windshield
Washer System
67 Transfer Case

Black plate (45,1)GMC Yukon/Yukon XL Owner Manual - 2011
Vehicle Care 10-45
J-CaseFuses Usage
68 Stud 1 (Trailer Connector
Battery Power)
69 Mid-Bussed Electrical
Center 1
70 Climate Control Blower
71 Power Liftgate Module
72 Left Bussed Electrical
Center 2
Relays Usage
FAN HI Cooling Fan High
Speed
FAN LO Cooling Fan Low
Speed
FAN
CNTRL Cooling Fan Control Relays Usage
HDLP
LO/HID Low-Beam Headlamp
FOG
LAMP Front Fog Lamps
A/C
CMPRSR Air Conditioning
Compressor
STRTR Starter
PWR/TRN Powertrain
FUEL
PMP Fuel Pump
PRK
LAMP Parking Lamps
REAR
DEFOG Rear Defogger
RUN/
CRNK Switched PowerInstrument Panel Fuse
Block
The instrument panel fuse block
access door is located on the driver
side edge of the instrument panel.
Pull off the cover to access the fuse
block.

Black plate (93,1)GMC Yukon/Yukon XL Owner Manual - 2011
Vehicle Care 10-93
Towing
Towing the Vehicle
Notice:To avoid damage, the
disabled vehicle should be
towed with all four wheels off
the ground. Care must be taken
with vehicles that have low
ground clearance and/or special
equipment. Always flatbed on a
car carrier.
Consult your dealer or a
professional towing service if the
disabled vehicle must be towed.
See Roadside Assistance Program
on page 13‑6.
To tow the vehicle behind another
vehicle for recreational purposes,
such as behind a motor home, see
“Recreational Vehicle Towing” in this
section.
Recreational Vehicle
Towing
If the vehicle has a hybrid engine,
see the hybrid manual for more
information.
Recreational vehicle towing means
towing the vehicle behind another
vehicle –such as behind a motor
home. The two most common types
of recreational vehicle towing are
known as dinghy towing and dolly
towing. Dinghy towing is towing the
vehicle with all four wheels on the
ground. Dolly towing is towing the
vehicle with two wheels on the
ground and two wheels up on a
device known as a dolly. Here are some important things to
consider before recreational vehicle
towing:.What is the towing capacity
of the towing vehicle? Be
sure to read the tow
vehicle manufacturer's
recommendations.
.What is the distance that will be
travelled? Some vehicles have
restrictions on how far and how
long they can tow.
.Is the proper towing equipment
going to be used? See your
dealer or trailering professional
for additional advice and
equipment recommendations.
.Is the vehicle ready to be
towed? Just as preparing the
vehicle for a long trip, make sure
the vehicle is prepared to be
towed.

Black plate (3,1)GMC Yukon/Yukon XL Owner Manual - 2011
Service and Maintenance 11-3
If the engine oil life system is reset
accidentally, service the vehicle
within 5 000 km/3,000 miles since
the last service. Reset the oil life
system whenever the oil is changed.
SeeEngine Oil Life System on
page 10‑10.
Every Engine Oil Change
.Change engine oil and filter.
Reset oil life system. See
Engine Oil on page 10‑7 and
Engine Oil Life System on
page 10‑10. An Emission
Control Service.
.Engine coolant level check. See
Engine Coolant on page 10‑17.
.Engine cooling system
inspection. Visual inspection
of hoses, pipes, fittings, and
clamps and replacement,
if needed.
.Windshield washer fluid level
check. See Washer Fluid on
page 10‑25.
.Windshield wiper blade
inspection for wear, cracking,
or contamination and windshield
and wiper blade cleaning,
if contaminated. See Exterior
Care on page 10‑98. Worn
or damaged wiper blade
replacement. See Wiper Blade
Replacement on page 10‑33.
.Tire inflation pressures check.
See Tire Pressure on
page 10‑56.
.Tire wear inspection. See Tire
Inspection on page 10‑62.
.Rotate tires if necessary. See
Tire Rotation on page 10‑62.
.Fluids visual leak check (or
every 12 months, whichever
occurs first). A leak in any
system must be repaired and
the fluid level checked.
.Engine air cleaner filter
inspection. See Engine Air
Cleaner/Filter on page 10‑15.
.Brake system inspection (or
every 12 months, whichever
occurs first).
.Steering and suspension
inspection. Visual inspection
for damaged, loose, or missing
parts or signs of wear.
.Lubricate the front suspension,
steering linkage, and parking
brake cable guides. For vehicles
mainly driven in heavy city
traffic in hot weather, in hilly
or mountainous terrain, when
frequently towing a trailer,
or used for taxi, police,
or delivery service, lubricate
every 5 000 km/3,000 miles.
Control arm ball joints on
2500 series vehicles require
lubrication but should not
be lubricated unless their
temperature is −12°C (10°F)
or higher, or they could be
damaged. Control arm ball
joints on 1500 series vehicles
are maintenance‐free.