2010 GMC YUKON XL check engine

Driving with a Trailer
{WARNING:
When towing a trailer, exhaust gases may collect
at the rear of the vehicle and enter if the liftgate,
trunk/hatch, or rear-most window is open.
Engine exhaust contains carbon monoxide (CO)
which cannot be seen or smelled. It can cause
unconsciousness and even death.
To maximize safety when towing a trailer:
.Have the exhaust system inspected for leaks
and make necessary repairs before starting
a trip.
.Never drive with the liftgate, trunk/hatch,
or rear-most window open.
.Fully open the air outlets on or under the
instrument panel.
.Adjust the Climate Control system to a setting
that brings in only outside air and set the fan
speed to the highest setting. See Climate
Control System in the Index.
For more information about carbon monoxide, see
Engine Exhaust on page 3‑52. Towing a trailer requires a certain amount of
experience. The combination you are driving is
longer and not as responsive as the vehicle itself.
Get acquainted with the handling and braking of the
rig before setting out for the open road.
Before starting, check all trailer hitch parts and
attachments, safety chains, electrical connectors,
lamps, tires and mirrors. If the trailer has electric
brakes, start the combination moving and then apply
the trailer brake controller by hand to be sure the
brakes work.
During the trip, check occasionally to be sure that the
load is secure and the lamps and any trailer brakes
still work.
Following Distance
Stay at least twice as far behind the vehicle ahead as
you would when driving the vehicle without a trailer.
This can help to avoid heavy braking and sudden turns.
Passing
More passing distance is needed when towing a trailer.
The combination will not accelerate as quickly and is
longer so it is necessary to go much farther beyond the
passed vehicle before returning to the lane.
5-64

Backing Up
Hold the bottom of the steering wheel with one hand.
Then, to move the trailer to the left, move that hand to
the left. To move the trailer to the right, move your hand
to the right. Always back up slowly and, if possible,
have someone guide you.
Making Turns
Notice:Making very sharp turns while trailering
could cause the trailer to come in contact with the
vehicle. The vehicle could be damaged. Avoid
making very sharp turns while trailering.
When turning with a trailer, make wider turns than
normal. Do this so the trailer will not strike soft
shoulders, curbs, road signs, trees or other objects.
Avoid jerky or sudden maneuvers. Signal well in
advance.
If the trailer turn signal bulbs burn out, the arrows on the
instrument panel will still flash for turns. It is important to
check occasionally to be sure the trailer bulbs are still
working.
Driving On Grades
Reduce speed and shift to a lower gear beforestarting
down a long or steep downgrade. If the transmission
is not shifted down, the brakes might get hot and no
longer work well.
Vehicles can tow in D (Drive). Shift the transmission to
a lower gear if the transmission shifts too often under
heavy loads and/or hilly conditions.
The tow/haul mode may be used if the transmission
shifts too often. See Tow/Haul Mode on page 3‑39.
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a
lower temperature than at normal altitudes. If the engine
is turned off immediately after towing at high altitude on
steep uphill grades, the vehicle may show signs similar
to engine overheating. To avoid this, let the engine run
while parked, preferably on level ground, with the
automatic transmission in P (Park) for a few minutes
before turning the engine off. If the overheat warning
comes on, see Engine Overheating on page 6‑36.
5-65

Leaving After Parking on a Hill
1. Apply and hold the brake pedal.
2. Start the engine
3. Shift into a gear
4. Release the parking brake
5. Let up on the brake pedal.
6. Drive slowly until the trailer is clear of the chocks.
7. Stop and have someone pick up and store thechocks.
Maintenance When Trailer Towing
The vehicle needs service more often when pulling a
trailer. See this manual's Maintenance Schedule or
Index for more information. Things that are especially
important in trailer operation are automatic transmission
fluid, engine oil, axle lubricant, belts, cooling system
and brake system. It is a good idea to inspect these
before and during the trip.
Check periodically to see that all hitch nuts and bolts
are tight.
Trailer Wiring Harness
The vehicle is equipped with the following wiring
harnesses for towing a trailer.
Basic Trailer Wiring
The trailer wiring harness, with a seven-pin connector,
is located at the rear of the vehicle and is tied to the
vehicle's frame. The harness connector can be plugged
into a seven-pin universal heavy-duty trailer connector
available through your dealer.
The seven-wire harness contains the following trailer
circuits:
.Yellow: Left Stop/Turn Signal
.Dark Green: Right Stop/Turn Signal
.Brown: Taillamps
.White: Ground
.Light Green: Back-up Lamps
.Red: Battery Feed*
.Dark Blue: Trailer Brake*
*The fuses for these two circuits are installed in the
underhood electrical center, but the wires are not
connected. They should be connected by your dealer
or a qualified service center.
5-67

Section 6 Service and Appearance Care
Service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4
Accessories and Modifications . . . . . . . . . . . . . . . . . . 6-4
California Proposition 65 Warning . . . . . . . . . . . . . . . 6-5
California Perchlorate Materials Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5
Doing Your Own Service Work . . . . . . . . . . . . . . . . . . 6-5
Adding Equipment to the Outside of the Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6
Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6
Gasoline Octane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
Gasoline Specifications . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
California Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8
Additives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8
Fuel E85 (85% Ethanol) . . . . . . . . . . . . . . . . . . . . . . . . . 6-9
Fuels in Foreign Countries . . . . . . . . . . . . . . . . . . . . . 6-10
Filling the Tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-11
Filling a Portable Fuel Container . . . . . . . . . . . . . . . 6-13
Checking Things Under the Hood . . . . . . . . . . . . . . .6-14
Hood Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-14
Engine Compartment Overview . . . . . . . . . . . . . . . . 6-16
Engine Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18
Engine Oil Life System . . . . . . . . . . . . . . . . . . . . . . . . 6-20
Engine Air Cleaner/Filter . . . . . . . . . . . . . . . . . . . . . . . 6-22
Automatic Transmission Fluid (4-Speed Transmission) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-24 Automatic Transmission Fluid (6-Speed
Transmission) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-27
Cooling System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-30
Engine Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-32
Engine Overheating . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-36
Overheated Engine Protection Operating Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-39
Engine Fan Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-39
Power Steering Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . 6-40
Windshield Washer Fluid . . . . . . . . . . . . . . . . . . . . . . 6-41
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-42
Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-45
Jump Starting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-46
Rear Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-51
Four-Wheel Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-52
Front Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-53
Headlamp Aiming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-55
Bulb Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-58
Halogen Bulbs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-58
Taillamps, Turn Signal, Stoplamps and Back-up Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-58
License Plate Lamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-60
Replacement Bulbs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-60
Windshield Wiper Blade Replacement . . . . . . . . . . .6-61
6-1

This vehicle has an airbag system. Before attempting
to do your own service work, seeServicing Your
Airbag-Equipped Vehicle on page 2‑99.
Keep a record with all parts receipts and list the
mileage and the date of any service work performed.
See Maintenance Record on page 7‑15.
Adding Equipment to the Outside of
the Vehicle
Things added to the outside of the vehicle can affect
the airflow around it. This can cause wind noise and
can affect fuel economy and windshield washer
performance. Check with your dealer before adding
equipment to the outside of the vehicle.
Fuel
Use of the recommended fuel is an important part
of the proper maintenance of this vehicle. To help
keep the engine clean and maintain optimum vehicle
performance, we recommend the use of gasoline
advertised as TOP TIER Detergent Gasoline.
Look for the TOP TIER label on the fuel pump to
ensure gasoline meets enhanced detergency standards
developed by auto companies. A list of marketers
providing TOP TIER Detergent Gasoline can be
found at www.toptiergas.com.The 8th digit of the Vehicle Identification Number (VIN)
shows the code letter or number that identifies the
vehicle's engine. The VIN is at the top left of the
instrument panel. See Vehicle Identification Number
(VIN) on page 6‑117.
6-6

California Fuel
If the vehicle is certified to meet California Emissions
Standards, it is designed to operate on fuels that meet
California specifications. See the underhood emission
control label. If this fuel is not available in states
adopting California emissions standards, the vehicle
will operate satisfactorily on fuels meeting federal
specifications, but emission control system performance
might be affected. The malfunction indicator lamp could
turn on and the vehicle might fail a smog‐check test.
SeeMalfunction Indicator Lamp
on page 4‑39. If this
occurs, return to your authorized dealer for diagnosis.
If it is determined that the condition is caused by the
type of fuel used, repairs might not be covered by the
vehicle warranty.
Additives
To provide cleaner air, all gasolines in the United States
are now required to contain additives that help prevent
engine and fuel system deposits from forming, allowing
the emission control system to work properly. In most
cases, nothing should have to be added to the fuel.
However, some gasolines contain only the minimum
amount of additive required to meet U.S. Environmental
Protection Agency regulations. To help keep fuel
injectors and intake valves clean, or if the vehicle experiences problems due to dirty injectors or valves,
look for gasoline that is advertised as TOP TIER
Detergent Gasoline.
For customers who do not use TOP TIER Detergent
Gasoline regularly, one bottle of GM Fuel System
Treatment PLUS, added to the fuel tank at every engine
oil change, can help clean deposits from fuel injectors
and intake valves. GM Fuel System Treatment PLUS
is the only gasoline additive recommended by General
Motors.
Also, your dealer has additives that will help correct and
prevent most deposit‐related problems.
Gasolines containing oxygenates, such as ethers
and ethanol, and reformulated gasolines might be
available in your area. We recommend that you use
these gasolines, if they comply with the specifications
described earlier. However, E85 (85% ethanol) and
other fuels containing more than 10% ethanol must
not be used in vehicles that were not designed for
those fuels.
Notice:
This vehicle was not designed for fuel that
contains methanol. 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.
6-8

Checking Things Under
the Hood
{WARNING:
An electric fan under the hood can start up and
injure you even when the engine is not running.
Keep hands, clothing, and tools away from any
underhood electric fan.
{WARNING:
Things that burn can get on hot engine parts and
start a fire. These include liquids like fuel, oil,
coolant, brake fluid, windshield washer and other
fluids, and plastic or rubber. You or others could
be burned. Be careful not to drop or spill things
that will burn onto a hot engine.
Hood Release
To open the hood:
1. Pull the handle withthis symbol on it. It is
located inside the
vehicle to the lower left
of the steering wheel.
6-14

A.Engine Air Cleaner/Filter on page 6‑22.
B. Coolant Surge Tank and Pressure Cap. See Cooling System on page 6‑30.
C. Remote Positive (+) Terminal. See Jump Starting
on page 6‑46.
D. Battery on page 6‑45.
E. Engine Oil Fill Cap. See “When to Add Engine Oil”
under Engine Oil on page 6‑18.
F. Automatic Transmission Dipstick. See “Checking
the Fluid Level” underAutomatic Transmission
Fluid (4-Speed Transmission)
on page 6‑24or Automatic Transmission Fluid (6-Speed
Transmission) on page 6‑27.
G. Remote Negative (−) Terminal (Out of View). See Jump Starting on page 6‑46. H. Engine Oil Dipstick (Out of View). See
“Checking
Engine Oil” underEngine Oil on page 6‑18.
I. Engine Cooling Fan. See Cooling System
on
page 6‑30.
J. Power Steering Fluid Reservoir. See Power
Steering Fluid on page 6‑40.
K. Brake Master Cylinder Reservoir. See “Brake
Fluid” under Brakes on page 6‑42.
L. Underhood Fuse Block on page 6‑122.
M. Windshield Washer Fluid Reservoir. See “Adding
Washer Fluid” underWindshield Washer Fluid
on
page 6‑41.
6-17