2007 GMC YUKON XL ECU

Four-Wheel-Drive Vehicles
Use the following procedure to tow your vehicle:
1. Shift the transmission to PARK (P).
2. Turn the engine off, but leave the ignition on.
3. Firmly set the parking brake.
4. Securely attach the vehicle being towed to the
tow vehicle.
{CAUTION:
Shifting a four-wheel-drive vehicle’s
transfer case into NEUTRAL can cause
your vehicle to roll even if the
transmission is in PARK (P). You or
others could be injured. Make sure the
parking brake is rmly set before you shift
the transfer case to NEUTRAL.
5. Shift the transfer case to NEUTRAL (N). See
Four-Wheel Drive on page 146for the proper
procedure to select the NEUTRAL (N)
position for your vehicle.
6. Release the parking brake only after the
vehicle being towed is rmly attached to
the towing vehicle.
7. Turn the ignition off.
402

Dolly Towing
Two-Wheel-Drive Vehicles
Notice:If you tow a two-wheel-drive vehicle
with the rear wheels on the ground, the
transmission could be damaged. The repairs
would not be covered by your warranty. Never
tow your vehicle with the rear wheels on the
ground.
Two-wheel-drive vehicles should not be
towed with the rear wheels on the ground.
Two-wheel-drive transmissions have no provisions
for internal lubrication while being towed.
Two-wheel-drive vehicles can be towed on a dolly
with the front wheels on the ground provided
that the wheels are straight.
Four-Wheel-Drive Vehicles
If your vehicle is equipped with StabiliTrak®,itis
not designed to be dolly towed. If you need to tow
your vehicle, see “Dinghy Towing” earlier in this
section.If your vehicle is not equipped with StabiliTrak
®,
use the following procedure to tow your vehicle:
1. Drive the vehicle up onto the tow dolly.
2. Shift the transmission to PARK (P).
3. Turn the engine off, but leave the ignition on.
4. Firmly set the parking brake.
5. Securely attach the vehicle being towed to the
tow dolly.
403

Driving with a Trailer
{CAUTION:
If you have a rear-most window open and
you pull a trailer with your vehicle, carbon
monoxide (CO) could come into your
vehicle. You cannot see or smell CO. It can
cause unconsciousness or death. See
Engine Exhaust on page 155. To maximize
your safety when towing a trailer:
Have your exhaust system inspected
for leaks, and make necessary repairs
before starting on your trip.
Keep the rear-most windows closed.If exhaust does come into your vehicle
through a window in the rear or another
opening, drive with your front, main
heating or cooling system on and with
the fan on any speed. This will bring
fresh, outside air into your vehicle.
Do not use the climate control setting
for maximum air because it only
recirculates the air inside your vehicle.
SeeClimate Control System on
page 210.Towing a trailer requires a certain amount of
experience. Before setting out for the open road,
you’ll want to get to know your rig. Acquaint yourself
with the feel of handling and braking with the added
weight of the trailer. And always keep in mind that
the vehicle you are driving is now a good deal
longer and not nearly as responsive as your vehicle
is by itself.
Before you start, check all trailer hitch parts and
attachments, safety chains, electrical connector,
lamps, tires and mirror adjustment. If the trailer has
electric brakes, start your vehicle and trailer moving
and then apply the trailer brake controller by hand
to be sure the brakes are working. This lets you
check your electrical connection at the same time.
During your trip, check occasionally to be sure
that the load is secure, and that the lamps and any
trailer brakes are still working.
416

Checking Coolant
The coolant surge tank is located in the engine
compartment on the passenger’s side of the
vehicle. SeeEngine Compartment Overview on
page 436for more information on location.
{CAUTION:
Turning the surge tank pressure cap when
the engine and radiator are hot can allow
steam and scalding liquids to blow out
and burn you badly. Never turn the surge
tank pressure cap — even a little — when
the engine and radiator are hot.
The vehicle must be on a level surface. When
your engine is cold, the coolant level should be at
the FULL COLD mark.
Adding Coolant
If you need more coolant, add the proper
DEX-COOL®coolant mixture at the surge tank,
but only when the engine is cool.
{CAUTION:
You can be burned if you spill coolant on
hot engine parts. Coolant contains
ethylene glycol, and it will burn if the
engine parts are hot enough. Do not spill
coolant on a hot engine.
When replacing the pressure cap, make sure it is
hand-tight and fully seated.
Coolant Surge Tank Pressure Cap
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.
The coolant surge tank pressure cap must be fully
installed on the coolant surge tank. SeeEngine
Compartment Overview on page 436for more
information on location.
451

The Tire Pressure Monitor System (TPMS)
operates on a radio frequency and complies
with RSS-210 of Industry and Science Canada.
Operation is subject to the following
two conditions:
1. This device may not cause interference.
2. This device must accept any interference
received, including interference that may
cause undesired operation of the device.
Changes or modications to this system by other
than an authorized service facility could void
authorization to use this equipment.
Tire Inspection and Rotation
Tires should be rotated every 5,000 to 8,000 miles
(8 000 to 13 000 km).
Any time you notice unusual wear, rotate your
tires as soon as possible and check wheel
alignment. Also check for damaged tires or wheels.
SeeWhen It Is Time for New Tires on page 499
andWheel Replacement on page 504for
more information.Make sure the spare tire is stored securely. Push,
pull, and then try to rotate or turn the tire. If it
moves, use the ratchet/wheel wrench to tighten the
cable. SeeChanging a Flat Tire on page 508.
The purpose of regular rotation is to achieve more
uniform wear for all tires on the vehicle. The
rst rotation is the most important. SeeScheduled
Maintenance on page 555.
When rotating your vehicle’s tires, always use the
correct rotation pattern shown here.
Do not include the spare tire in the tire rotation.
497

Tire Chains
{CAUTION:
If your vehicle has P265/65R18 or
P275/55R20 size tires, do not use tire
chains. They can damage your vehicle
because 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 you to lose
control of your vehicle and you or others
may be injured in a crash.
Use another type of traction device only if
its manufacturer recommends it for use
on your vehicle and tire size combination
and road conditions. Follow that
manufacturer’s instructions.
CAUTION: (Continued)
CAUTION: (Continued)
To help avoid damage to your vehicle,
drive slowly, readjust or remove the
device if it is contacting your vehicle, and
do not spin your vehicle’s wheels.
If you do nd traction devices that will t,
install them on the rear tires.
Notice:If your vehicle has P265/70R17 size
tires, use tire chains only where legal and only
when you must. Use chains that are the
proper size for your vehicle’s 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 you
can hear the chains contacting your 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 your vehicle.
506

4. Repeat this procedure at least two times.
If the spare tire lowers to the ground,
continue with Step 5 ofRemoving the Spare
Tire and Tools on page 509.
5. If the spare tire does not lower, turn the wheel
wrench counterclockwise until approximately
6 inches (15 cm) of cable is exposed.
6. Stand the wheel blocks on their shortest ends,
with the backs facing each other.
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.
520

3. Assemble the two jack handle extensions (D)
and wheel wrench (E) as shown.
4. Insert the open end
of the extension (I)
through the hole in
the rear bumper (J)
(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. You cannot overtighten the cable.
7. Make sure the tire is stored securely. 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.
524