2006 GMC YUKON tow

Overheated Engine Protection
Operating Mode
If an overheated engine condition exists and the
REDUCED ENGINE POWER message is displayed,
an overheat protection mode which alternates ring
groups of cylinders helps prevent engine damage.
In this mode, you will notice a loss in power and
engine performance. This operating mode allows your
vehicle to be driven to a safe place in an emergency.
Driving extended miles (km) 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. SeeEngine Oil
on page 5-15.
Cooling System
When you decide it is safe to lift the hood, here is what
you will see:
A. Coolant Surge Tank
B. Coolant Surge Tank Pressure Cap
C. Engine Cooling Fan8.1L V8 Engines
5-30

4. With the coolant surge tank pressure cap off, start
the engine and let it run until you can feel the upper
radiator hose 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. Then replace the pressure cap. Be sure the
pressure cap is hand-tight and fully seated.
Engine Fan Noise
If your vehicle is equipped with 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. 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 you may hear an increase in
fan noise. 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.
You may also hear this fan noise when you start the
engine. It will go away as the fan clutch partially
disengages.
If your vehicle is equipped with electric cooling fans, you
may hear the fans spinning at low speed during most
everyday driving. The fans may turn off if no cooling is
required. Under heavy vehicle loading, trailer towing,
and/or high outside temperatures, or if you are operating
your air conditioning system, the fans change to high
speed and you may hear an increase in fan noise.
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.
5-35

3. Press the retainer clip (B), located behind the turn
signal assembly, towards the outside of the vehicle.
4. Pull the turn signal assembly out of the vehicle.
5. Press the locking release lever, turn the bulb
socket counterclockwise and remove it from the
turn signal assembly.
6. Remove the old bulb from the bulb socket.
7. Install a new bulb into the bulb socket.
8. Insert the bulb socket into the turn signal assembly
and turn it clockwise until it locks.9. Reinstall the turn signal assembly back into the
vehicle placing the hook and posts on the inner
side into the alignment holes rst, then the
outer side into the retainer bracket until you hear
a click.
10. Reinstall the headlamp assembly.
Side Identication Marker Lamps
To replace a side identication marker bulb,
do the following:
1. Locate the lamp gasket near the rear wheel to
expose the service slot and pull back the edge.
2. Using a at tool, push into the slot to release the
lamp housing.
3. Pull the housing out to expose the wiring harness
and connector.
4. Unplug the lamp assembly harness from the
housing.
5. Unplug the lamp.
6. Put in a new lamp and snap it into the housing.
7. Reinstall the lamp housing.
5-52

Vehicles that have the Tire Pressure Monitor System
(TPMS) will need to have the TPMS sensors reset after
a tire rotation. See “TPMS Sensor Identication Codes”
underTire Pressure Monitor System on page 5-64.
Make certain that all wheel nuts are properly tightened.
See “Wheel Nut Torque” underCapacities and
Specications on page 5-114.
{CAUTION:
Rust or dirt on a wheel, or on the parts to
which it is fastened, can make wheel nuts
become loose after a time. The wheel could
come off and cause an accident. When you
change a wheel, remove any rust or dirt from
places where the wheel attaches to the vehicle.
In an emergency, you can use a cloth or a
paper towel to do this; but be sure to use a
scraper or wire brush later, if needed, to get
all the rust or dirt off. SeeChanging a Flat
Tire on page 5-76.
When It Is Time for New Tires
One way to tell when
it is time for new tires
is to check the treadwear
indicators, which will
appear when your tires
have only 1/16 inch
(1.6 mm) or less of
tread remaining. Some
commercial truck tires
may not have treadwear
indicators.
You need a new tire if any of the following statements
are true:
You can see the indicators at three or more places
around the tire.
You can see cord or fabric showing through the
tire’s rubber.
The tread or sidewall is cracked, cut or snagged
deep enough to show cord or fabric.
The tire has a bump, bulge, or split.
The tire has a puncture, cut, or other damage
that cannot be repaired well because of the size
or location of the damage.
5-69

CAUTION: (Continued)
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. 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 you have a tire size other than
P265/75R16, LT265/75R16, P265/70R16, P265/70R17,
or P275/55R20 use tire chains only where legal
and only when you must. Use chains that are the
proper size for your 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.
If a Tire Goes Flat
It is unusual for a tire to blowout while you are driving,
especially if you maintain your vehicle’s tires properly.
If air goes out of a tire, it is much more likely to leak out
slowly. But if you should ever have a blowout, here
are a few tips about what to expect and what to do:
If a front tire fails, the at tire will create a drag that
pulls the vehicle toward that side. Take your foot off the
accelerator pedal and grip the steering wheel rmly.
Steer to maintain lane position, and then gently brake
to a stop well out of the traffic lane.
5-75

2. Assemble the wheel wrench (H) and the two jack
handle extensions (I) as shown.
3. Insert the spare tire
end (open end) (F)
of the extension
through the hole (G)
in the rear bumper.
Be sure the hoist end of the extension connects to
the hoist shaft (E). The ribbed square end of the
extension is used to lower the spare tire.4. Turn the wheel wrench (H) counterclockwise to
lower the spare tire to the ground. Continue to
turn the wheel wrench until the spare tire can be
pulled out from under the vehicle.
If the spare tire does not lower to the ground, the
secondary latch is engaged causing the tire not to
lower. SeeSecondary Latch System on page 5-88.
5. Use the wheel wrench
hook that allows you
to pull the hoist
cable towards you
to assist in reaching
the spare tire.
5-80

{CAUTION:
Rust or dirt on the wheel, or on the parts to
which it is fastened, can make the wheel nuts
become loose after a time. The wheel could
come off and cause an accident. When you
change a wheel, remove any rust or dirt from
the places where the wheel attaches to the
vehicle. In an emergency, you can use a cloth
or a paper towel to do this; but be sure to
use a scraper or wire brush later, if needed,
to get all the rust or dirt off.
5. Remove any rust or dirt
from the wheel bolts,
mounting surfaces
and spare wheel.
{CAUTION:
Never use oil or grease on studs or nuts.
If you do, the nuts might come loose.
Your wheel could fall off, causing a serious
accident.
6. Put the wheel nuts
back on with the
rounded end of the
nuts toward the
wheel after mounting
the spare.
7. Tighten each wheel nut by hand. Then use the
wheel wrench to tighten the nuts until the wheel
is held against the hub.
8. Turn the wheel wrench counterclockwise to lower
the vehicle. Lower the jack completely.
5-86

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 5-78.
5. If the spare does not lower, turn the 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.
5-89