2012 GMC YUKON ECU

Black plate (21,1)GMC Yukon/Yukon XL Owner Manual - 2012
Vehicle Care 10-21
4. With the coolant surge tankpressure cap off, start the
engine and let it run until the
upper radiator hose can be felt
getting hot. Watch out for the
engine cooling fan.
By this time, the coolant level
inside the coolant surge tank
may be lower. If the level is
lower, add more of the proper
mixture to the coolant surge tank
until the level reaches the FULL
COLD mark. 5. Replace the pressure cap. Be
sure the pressure cap is
hand-tight and fully seated.
6. Verify coolant level after engine is shut off and the coolant is
cold. If necessary, repeat coolant
fill procedure Steps 1 through 6.
Notice: If the pressure cap is not
tightly installed, coolant loss and
possible engine damage may
occur. Be sure the cap is properly
and tightly secured.
Engine Overheating
The vehicle has several indicators
to warn of engine overheating.
There is a coolant temperature
gauge on your vehicle's instrument
panel. See Engine Coolant
Temperature Gauge on page 5‑16. In addition, ENGINE OVERHEATED
STOP ENGINE, ENGINE
OVERHEATED IDLE ENGINE, and
an ENGINE POWER IS REDUCED
message comes on in the Driver
Information Center (DIC) on the
instrument panel. See
Engine
Cooling System Messages on
page 5‑39 andEngine Power
Messages on page 5‑41.
If the decision is made not to lift the
hood when this warning appears,
but instead get service help right
away. See Roadside Assistance
Program on page 13‑5.
If the decision is made to lift the
hood, make sure the vehicle is
parked on a level surface.

Black plate (70,1)GMC Yukon/Yukon XL Owner Manual - 2012
10-70 Vehicle Care
Tire Chains
If your vehicle is a Hybrid, see the
Hybrid Supplement for more
information.
{WARNING
If the vehicle has P265/65R18 or
P275/55R20 size tires, do not use
tire chains. There is not enough
clearance. Tire chains used on a
vehicle without the proper amount
of clearance can cause damage
to the brakes, suspension,
or other vehicle parts. The area
damaged by the tire chains could
cause loss of control and a crash.(Continued)
WARNING (Continued)
Use another type of traction
device only if its manufacturer
recommends it for the vehicle's
tire size combination and
road conditions. Follow that
manufacturer's instructions. To
avoid vehicle damage, drive slow
and readjust or remove the
traction device if it is contacting
the vehicle. Do not spin the
wheels.
If traction devices are used, install
them on the rear tires. Notice:
If the vehicle has
P265/70R17 size tires, use tire
chains only where legal and only
when necessary. Use chains that
are the proper size for the tires.
Install them on the rear tires only.
Do not use chains on the front
tires.
Tighten them as tightly as
possible with the ends securely
fastened. Drive slowly and
follow the chain manufacturer's
instructions. If the chains contact
the vehicle, stop and retighten
them. If the contact continues,
slow down until it stops. Driving
too fast or spinning the wheels
with chains on will damage the
vehicle.

Black plate (82,1)GMC Yukon/Yukon XL Owner Manual - 2012
10-82 Vehicle Care
Pull the pin through the center of
the wheel. Tilt the retainer down
through the center wheel
opening.
Make sure the retainer is fully
seated across the underside of
the wheel.
3. Assemble the two jack handleextensions (D) and wheel
wrench (E) as shown.
4. Insert the open end of theextension (J) through the hole in
the rear bumper (I) (hoist shaft
access hole).
5. Raise the tire part way upward. Make sure the retainer is seated
in the wheel opening.
6. Raise the tire fully against the underside of the vehicle by
turning the wheel wrench
clockwise until you hear two
clicks or feel it skip twice. The
cable cannot be overtightened.
7. Make sure the tire is storedsecurely. Push, pull (A), and then
try to turn (B) the tire. If the tire
moves, use the wheel wrench to
tighten the cable.
8. Reinstall the spare tire lock.
9. Reinstall the hoist shaft access cover.

Black plate (83,1)GMC Yukon/Yukon XL Owner Manual - 2012
Vehicle Care 10-83
To store the tools, do the following:
A. Wheel Blocks
B. Tool Bag with Jack Tools
C. Retaining Bracket
D. Wing Nut Retaining Tool Bag
E. JackF. Wing Nut Retaining Wheel
Blocks
G. Jack Knob
1. Return the tools (wheel wrench, jack handle, and jack handle
extensions) to the tool bag (B).
2. Assemble wheel blocks (A) and jack (E) together with the
wing nut (F).
3. Position the jack (E) and wheel blocks (A) in the driver side trim
panel over the wheelhouse.
4. Turn the jack knob (G) clockwise until the jack is secured tight in
the mounting bracket. Be sure to
position the holes in the base of
the jack onto the pin in the
mounting bracket. 5. Use the retaining bracket (C) to
fasten the tool bag (B) on the
stud and turn the wing nut (D)
clockwise to secure.
6. Return the storage tray to its
original stored position.

Black plate (85,1)GMC Yukon/Yukon XL Owner Manual - 2012
Vehicle Care 10-85
A. Jack
B. Wheel Blocks
7. Place the bottom edge of the jack (A) on the wheel blocks (B),
separating them so that the jack
is balanced securely.8. Attach the jack handle,extension, and wheel wrench to
the jack and place it (with the
wheel blocks) under the vehicle
toward the front of the rear
bumper.9. Position the center lift point ofthe jack under the center of the
spare tire.
10. Turn the wrench clockwise to raise the jack until it lifts the
end fitting.
11. Continue raising the jack until the spare tire stops moving
upward and is held firmly in
place. The secondary latch has
released and the spare tire is
balancing on the jack.

Black plate (94,1)GMC Yukon/Yukon XL Owner Manual - 2012
10-94 Vehicle Care
Dinghy Towing
Two-Wheel-Drive Vehicles and
Four-Wheel Drive Vehicles with a
Single Speed Automatic
Transfer Case
Notice:If the vehicle is towed
with all four wheels on the
ground, the drivetrain
components could be damaged.
The repairs would not be covered
by the vehicle warranty. Do not
tow the vehicle with all four
wheels on the ground. Two-wheel-drive vehicles and
four-wheel drive vehicles with a
single speed automatic transfer
case should not be towed with all
four wheels on the ground.
Two-wheel-drive transmissions have
no provisions for internal lubrication
while being towed. Four-wheel drive
vehicles with a single speed
automatic transfer case have no
neutral position and will spin the
transmission when the rear
wheels turn.
Four-Wheel Drive Vehicles with a
Two Speed Automatic
Transfer Case
Use the following procedure to
dinghy tow a four-wheel drive
vehicle with a two speed automatic
transfer case:
1. Position the vehicle being towed
behind the tow vehicle and shift
the transmission to P (Park).
2. Turn the engine off and firmly set the parking brake.
3. Securely attach the vehicle being towed to the tow vehicle.

Black plate (97,1)GMC Yukon/Yukon XL Owner Manual - 2012
Vehicle Care 10-97
6. Shift the transfer case toN (Neutral). See Four-Wheel
Drive (Two Speed Automatic
Transfer Case) on page 9‑37 or
Four-Wheel Drive (Single Speed
Automatic Transfer Case) on
page 9‑42.
7. Secure the vehicle to the dolly following the manufacturer's
instructions.
8. Release the parking brake only after the vehicle being towed is
firmly attached to the towing
vehicle.
9. Turn the ignition to LOCK/OFF.
After towing, see “Shifting Out of
N (Neutral)” underFour-Wheel Drive
(Two Speed Automatic Transfer
Case) on page 9‑37 orFour-Wheel
Drive (Single Speed Automatic
Transfer Case) on page 9‑42.Rear Towing (Rear Wheels Off
the Ground)
Two-Wheel-Drive Vehicles and
Four-Wheel Drive Vehicles with a
Single Speed Automatic
Transfer Case
Use the following procedure to dolly
tow the vehicle from the rear:
1. Attach the dolly to the tow
vehicle following the dolly
manufacturer's instructions. 2. Drive the rear wheels onto the
dolly.
3. Firmly set the parking brake. See Parking Brake on
page 9‑45.
4. Put the transmission in P (Park).
5. Secure the vehicle to the dolly following the manufacturer's
instructions.
6. Use an adequate clamping device designed for towing to
ensure that the front wheels are
locked into the straight position.
7. For four-wheel drive vehicles with a single speed automatic
transfer case, shift the transfer
case into Two-Wheel Drive High.
See Four-Wheel Drive (Two
Speed Automatic Transfer Case)
on page 9‑37 orFour-Wheel
Drive (Single Speed Automatic
Transfer Case) on page 9‑42.
8. Turn the ignition to LOCK/OFF.

Black plate (98,1)GMC Yukon/Yukon XL Owner Manual - 2012
10-98 Vehicle Care
Four-Wheel Drive Vehicles with a
Two Speed Automatic
Transfer Case
Use the following procedure to dolly
tow a four-wheel drive vehicle from
the rear:
1. Attach the dolly to the towvehicle following the dolly
manufacturer's instructions.
2. Drive the rear wheels onto the dolly.
3. Firmly set the parking brake. See Parking Brake on
page 9‑45.
4. Put the transmission in P (Park).
5. Secure the vehicle to the dolly following the manufacturer's
instructions.
6. Use an adequate clamping device designed for towing to
ensure that the front wheels are
locked into the straight position.{WARNING
Shifting a four-wheel-drive
vehicle's transfer case into
N (Neutral) can cause the vehicle
to roll even if the transmission is
in P (Park). The driver or others
could be injured. Make sure the
parking brake is firmly set before
the transfer case is shifted to
N (Neutral).
7. Shift the transfer case to N (Neutral). See Four-Wheel
Drive (Two Speed Automatic
Transfer Case) on page 9‑37 or
Four-Wheel Drive (Single Speed
Automatic Transfer Case) on
page 9‑42.
8. Turn the ignition to LOCK/OFF.
After towing, see “Shifting Out of
N (Neutral)” underFour-Wheel Drive
(Two Speed Automatic Transfer
Case) on page 9‑37 orFour-Wheel
Drive (Single Speed Automatic
Transfer Case) on page 9‑42.
Appearance Care
Exterior Care
Washing the Vehicle
To preserve the vehicle's finish,
wash it often and out of direct
sunlight.
Notice: Do not use petroleum
based, acidic, or abrasive
cleaning agents as they can
damage the vehicle's paint, metal,
or plastic parts. If damage
occurs, it would not be covered
by the vehicle's warranty.
Approved cleaning products can
be obtained from your dealer.
Follow all manufacturer
directions regarding correct
product usage, necessary safety
precautions, and appropriate
disposal of any vehicle care
product.