2005 GMC YUKON ECU

Here are some guidelines for safely carrying a snow
plow on your vehicle:
Make sure the weight on the front and rear axles
does not exceed the axle rating for each.
For the front axle, if more cargo or passengers
must be carried, appropriate counter ballast must be
installed rear of the rear axle. Counter ballast
must be properly secured so it will not move during
driving.
Follow the snow plow manufacturer’s
recommendations regarding rear ballast. Rear
ballast may be required to ensure a proper front and
rear weight distribution ratio, even though the
actual weight at the front axle may be less than the
front axle rating.
The snow plow manufacturer or installer can assist
you in determining the amount of rear ballast
required, to help make sure your snowplow/vehicle
combination does not exceed the GVW rating,
the front and rear axle ratings, and the front and
rear weight distribution ratio.
The total vehicle must not exceed the GVW rating.
Q:What is front axle reserve capacity, and how do
I calculate it?
A:Front axle reserve capacity is the difference
between your front gross axle weight rating (GAWR)
and the front axle weight of your vehicle with full
fuel and passengers. Basically, it is the amount of
weight you can add to your front axle before
reaching your front GAWR.
The front axle reserve capacity for your vehicle can be
found in the lower right corner of the Certication/Tire
label, as shown.
United States
Canada
4-58

Four-Wheel-Drive Vehicles (NR4 and NP8)
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 2-27orAll-Wheel
Drive with StabiliTrak
®on page 2-31for 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.
4-63

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 and the steering column has been locked.
Four-Wheel-Drive Vehicles
If your vehicle is equipped with StabiliTrak®,itisnot
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.
4-64

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.
Following Distance
Stay at least twice as far behind the vehicle ahead as
you would when driving your vehicle without a trailer.
This can help you avoid situations that require
heavy braking and sudden turns.
Passing
You’ll need more passing distance up ahead when
you’re towing a trailer. And, because you’re a good deal
longer, you’ll need to go much farther beyond the
passed vehicle before you can return to your lane.
Backing Up
Hold the bottom of the steering wheel with one hand.
Then, to move the trailer to the left, just 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.
If your vehicle is equipped with four-wheel steering and
if you use it while backing your trailer the same rules
apply. However, with four-wheel steering your rig
will respond more quickly and it may take additional
practice to get used to backing up with four-wheel
steering.
4-75

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 5-12
for 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.
If your vehicle is equipped with a low coolant sensor,
and the LOW COOLANT LEVEL message comes
on and stays on, it means you are low on engine
coolant. See “LOW COOLANT LEVEL” underDIC
Warnings and Messages on page 3-58.
Adding Coolant
If you need more coolant, add the proper DEX-COOL®
coolant mixtureat 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.
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 5-12for more
information on location.
5-26

Federal Communications Commission and
Industry and Science Canada
The TPM system operates on a radio frequency subject
to Federal Communications Commission (FCC) Rules
and with Industry and Science Canada.
This device complies with Part 15 of the FCC Rules and
with RSS-210 of Industry and Science Canada.
Operation is subject to the following two conditions:
(1) This device may not cause harmful interference, and
(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 5-70andWheel Replacement
on page 5-73for 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 5-76.
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 6-4.
5-68

Tire Chains
{CAUTION:
If your vehicle has P265/75R16, LT265/75R16,
P265/70R16 or P265/70R17 size tires, don’t use
tire chains. They can damage your vehicle
because there’s 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. To help avoid damage to your
vehicle, drive slowly, readjust or remove the
device if it’s contacting your vehicle, and don’t
spin your 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 or P265/70R17 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.
Don’t 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.
5-75

To release the spare tire from the secondary latch,
do the following:
1. Check under the
vehicle to see if the
cable end is visible.
If the cable is not
visible proceed
to Step 6.
2. If it is visible, rst try to tighten the cable by turning
the wheel wrench clockwise until you hear two clicks
or feel it skip twice. You cannot overtighten the cable.
3. Loosen the cable by turning the wrench
counterclockwise three or four turns.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.
5-88