2008 GMC YUKON DENALI ECU

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.
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Adding Coolant
If more coolant is needed, 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 5-12for more
information on location.
Engine Overheating
There is a coolant temperature gage on your vehicle’s
instrument panel. SeeEngine Coolant Temperature
Gage on page 3-41.
In addition, ENGINE OVERHEATED STOP ENGINE,
ENGINE OVERHEATED IDLE ENGINE, and a ENGINE
POWER IS REDUCED message comes on in the Driver
Information Center (DIC) on the instrument panel.
SeeDIC Warnings and Messages on page 3-56.
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When rotating your vehicle’s tires, always use the
correct rotation pattern shown here.
Do not include the spare tire in the tire rotation.
After the tires have been rotated, adjust the front
and rear ination pressures as shown on the Tire
and Loading Information label. SeeInflation - Tire
Pressure on page 5-60andLoading Your Vehicle
on page 4-34.
Reset the Tire Pressure Monitor System. SeeTire
Pressure Monitor Operation on page 5-64.Make certain that all wheel nuts are properly
tightened. See “Wheel Nut Torque” under
Capacities and Specifications 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 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 5-78.
Make sure the spare tire is stored securely. Push,
pull, and then try to rotate or turn the tire. If it
moves, tighten the cable. SeeStoring a Flat or
Spare Tire and Tools on page 5-94.
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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 5-79.
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.
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4. Insert the open end of
the extension (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.
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.
10. Reinstall the hitch cover.
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To store the tools:
A. Wheel Blocks
B. Tool Bag with Jack
Tools
C. Retaining Bracket
D. Wing Nut Retaining
Tool BagE. Jack
F. Wing Nut Retaining
Wheel Blocks
G. Wing Nut on Jack
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’s side trim panel over the wheelhouse.
4. Turn the wing nut (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.
Regular Wheelbase shown,
Extended Wheelbase similar.
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Owner Checks and Services
These owner checks and services should be performed
at the intervals specied to help ensure the safety,
dependability, and emission control performance of your
vehicle. Your dealer/retailer can assist you with these
checks and services.
Be sure any necessary repairs are completed at once.
Whenever any uids or lubricants are added to your
vehicle, make sure they are the proper ones, as shown
inRecommended Fluids and Lubricants on page 6-12.
At Each Fuel Fill
It is important to perform these underhood checks at
each fuel fill.
Engine Oil Level Check
Notice:It is important to check the engine oil
regularly and keep it at the proper level. Failure to
keep the engine oil at the proper level can cause
damage to the engine not covered by your warranty.
Check the engine oil level and add the proper oil if
necessary. SeeEngine Oil on page 5-13.
Engine Coolant Level Check
Check the engine coolant level and add DEX-COOL®
coolant mixture if necessary. SeeEngine Coolant
on page 5-23.
Windshield Washer Fluid Level Check
Check the windshield washer uid level in the windshield
washer uid reservoir and add the proper uid if
necessary.
At Least Once a Month
Tire Ination Check
Inspect your vehicle’s tires and make sure they are
inated to the correct pressures. Do not forget to check
the spare tire. SeeInflation - Tire Pressure on
page 5-60. Check to make sure the spare tire is stored
securely. SeeChanging a Flat Tire on page 5-78.
Tire Wear Inspection
Tire rotation may be required for high mileage highway
drivers prior to the Engine Oil Life System service
notication. Check the tires for wear and, if necessary,
rotate the tires. SeeTire Inspection and Rotation on
page 5-67.
6-9

Lock-out Service:Lock-out service will be covered
at no charge if you are unable to gain entry into your
vehicle. A remote unlock may be available if you
have an active OnStar
®subscription. To ensure
security, the driver must present personal
identication before lock-out service is provided. In
Canada, the vehicle registration is also required.
Emergency Tow From a Public Roadway or
Highway:Tow to the nearest dealership for warranty
service or in the event of a vehicle-disabling crash.
Winch-out assistance is provided when the vehicle is
mired in sand, mud, or snow.
Flat Tire Change:Installation of a spare tire in good
condition, when equipped and properly inated, is
covered at no charge. The customer is responsible
for the repair or replacement of the tire if not covered
by a warrantable failure.
Jump Start:A battery jump start is covered at no
charge if the vehicle does not start.
Trip Routing Service:Upon request, Roadside
Assistance will send you detailed, computer
personalized maps, highlighting your choice of either
the most direct route or the most scenic route to your
destination, anywhere in North America, along with
helpful travel information pertaining to your trip.Please allow three weeks before your planned
departure date. In Canada, trip routing requests will
be limited to six per calendar year.
Trip Interruption Benets and Assistance:In the
event of a warranty related vehicle disablement,
while en route and over 150 miles (250 kilometres)
from original point of departure, you may qualify for
trip interruption expense assistance. This assistance
covers reasonable reimbursement of up to a
maximum of $500. In Canada, maximums include:
(A) meals (maximum of $50/day), (B) lodging
(maximum of $100/night) and (C) alternate ground
transportation (maximum of $40/day). This benet is
to assist you with some of the unplanned expense
you may incur while waiting for your vehicle to be
repaired.
Original detailed receipts, and a copy of the repair
order are required. In Canada, pre-authorization is
also required.
Once authorization has been given, your advisor will
help you make any necessary arrangements and
explain how to claim for trip interruption expense
assistance.
Alternative Service (Canada only):There may be
times, when Roadside Assistance cannot provide
timely assistance. Your advisor may authorize you to
secure local emergency road service, and you will be
reimbursed up to $100 (Canadian) upon submission
of the original receipt to Roadside Assistance.
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