2004 GMC SIERRA DENALI stop start

Tow/Haul Mode
Tow/Haul is a feature that assists when pulling a heavy
trailer or a large or heavy load. The purpose of the
Tow/Haul mode is to:
·Reduce the frequency and improve the predictability
of transmission shifts when pulling a heavy trailer or
a large or heavy load.
·Provide the same solid shift feel when pulling a
heavy trailer or a large or heavy load as when
the vehicle is unloaded.
·Improve control of vehicle speed while requiring
less throttle pedal activity when pulling a heavy
trailer or a large or heavy load.
Your vehicle may be equipped with a switch at the end
of the shift lever which when pressed enables
Tow/Haul. When the switch is pressed, a light on the
instrument panel will illuminate to indicate that Tow/Haul
has been selected. Tow/Haul may be turned off by
pressing the switch again, at which time the indicator
light on the instrument panel will turn off. The vehicle will
automatically turn off Tow/Haul every time it is started.Tow/Haul is designed to be most effective when
the vehicle and trailer combined weight is at least
75 percent of the vehicle's Gross Combined Weight
Rating (GCWR). See Weight of the Trailer later in this
section. Tow/haul is most useful under the following
driving conditions:
·When pulling a heavy trailer or a large or heavy
load through rolling terrain.
·When pulling a heavy trailer or a large or heavy
load in stop and go traffic.
·When pulling a heavy trailer or a large or heavy
load in busy parking lots where improved low
speed control of the vehicle is desired.
Operating the vehicle in Tow/Haul when lightly loaded
or with no trailer at all will not cause damage. However,
there is no bene®t to the selection of Tow/Haul when
the vehicle is unloaded. Such a selection when unloaded
may result in unpleasant engine and transmission
driving characteristics and reduced fuel economy.
Tow/Haul is recommended only when pulling a heavy
trailer or a large or heavy load.
4-60

When You Are Ready to Leave After
Parking on a Hill
1. Apply your regular brakes and hold the pedal down
while you:
·start your engine,
·shift into a gear, and
·release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the
chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when you're
pulling a trailer. See the Maintenance Schedule for more
on this. Things that are especially important in trailer
operation are automatic transmission ¯uid (don't over®ll),
engine oil, axle lubricant, belts, cooling system and
brake system. Each of these is covered in this manual,
and the Index will help you ®nd them quickly. If
you're trailering, it's a good idea to review these sections
before you start your trip.
Check periodically to see that all hitch nuts and bolts
are tight.
4-68

Service............................................................5-3
Doing Your Own Service Work.........................5-3
Adding Equipment to the Outside of Your
Vehicle......................................................5-4
Fuel................................................................5-4
Gasoline Octane............................................5-4
Gasoline Speci®cations....................................5-4
California Fuel...............................................5-5
Additives.......................................................5-5
Fuels in Foreign Countries...............................5-6
Filling Your Tank............................................5-6
Filling a Portable Fuel Container.......................5-8
Checking Things Under the Hood.....................5-8
Hood Release................................................5-9
Engine Compartment Overview.......................5-10
Engine Oil...................................................5-11
Engine Air Cleaner/Filter................................5-16
Automatic Transmission Fluid.........................5-18
Engine Coolant.............................................5-21
Coolant Surge Tank Pressure Cap..................5-24
Engine Overheating.......................................5-25
Cooling System............................................5-28Engine Fan Noise.........................................5-34
Power Steering Fluid.....................................5-34
Windshield Washer Fluid................................5-35
Brakes........................................................5-36
Battery........................................................5-40
Jump Starting...............................................5-41
All-Wheel Drive..............................................5-46
Rear Axle.......................................................5-47
Front Axle......................................................5-48
Bulb Replacement..........................................5-49
Halogen Bulbs..............................................5-49
Headlamps..................................................5-49
Front Turn Signal, Sidemarker and Daytime
Running Lamps.........................................5-50
Roof Marker Lamps......................................5-52
Center High-Mounted Stoplamp (CHMSL) and
Cargo Lamp.............................................5-54
Pickup Box Identi®cation and Fender
Marker Lamps...........................................5-55
Taillamps.....................................................5-56
Replacement Bulbs.......................................5-57
Section 5 Service and Appearance Care
5-1

While refueling, hang the
fuel cap by the tether
using the hook located
on the inside of the
®ller door.
To remove the fuel cap,
turn it slowly to the left
(counterclockwise). It will
require more effort to turn
the fuel cap on the last turn
as you loosen it.
{CAUTION:
If you spill fuel and then something ignites it,
you could be badly burned. Fuel can spray out
on you if you open the fuel cap too quickly.
This spray can happen if your tank is nearly
full, and is more likely in hot weather. Open
the fuel cap slowly and wait for any ªhissº
noise to stop. Then unscrew the cap all
the way.Be careful not to spill fuel. Don't top off or over®ll your
tank and wait a few seconds after you've ®nished
pumping before you remove the nozzle. Clean any
spilled fuel from painted surfaces as soon as possible.
See
Cleaning the Outside of Your Vehicle on
page 5-99.
When you put the fuel cap back on, turn it to the right
(clockwise) until you hear a clicking sound. It will require
more effort to turn the fuel cap on the last turn as you
tighten it. Make sure you fully install the cap. The
diagnostic system can determine if the fuel cap has
been left off or improperly installed. this would allow fuel
to evaporate into the atmosphere. See
Malfunction
Indicator Lamp on page 3-40.
{CAUTION:
If a ®re starts while you are refueling, do not
remove the nozzle. Shut off the ¯ow of fuel by
shutting off the pump or by notifying the
station attendant. Leave the area immediately.
5-7

Notice:Use only engine oil identi®ed as meeting
GM Standard GM6094M and showing the American
Petroleum Institute Certi®ed For Gasoline Engines
starburst symbol. Failure to use the recommended
oil can result in engine damage not covered by
your warranty.
GM Goodwrench
žoil meets all the requirements for
your vehicle.
If you are in an area of extreme cold, where the
temperature falls below-20ÉF (-29ÉC), it is
recommended that you use either an SAE 5W-30
synthetic oil or an SAE 0W-30 oil. Both will provide
easier cold starting and better protection for your engine
at extremely low temperatures.
Engine Oil Additives
Do not add anything to your oil. The recommended oils
with the starburst symbol that meet GM Standard
GM6094M are all you will need for good performance
and engine protection.
When to Change Engine Oil (GM Oil
Life System)
Your vehicle has a computer system that lets you know
when to change the engine oil and ®lter. This is
based on engine revolutions and engine temperature,
and not on mileage. Based on driving conditions,
the mileage at which an oil change will be indicated can
vary considerably. For the oil life system to work
properly, you must reset the system every time the oil is
changed.
When the system has calculated that oil life has been
diminished, it will indicate that an oil change is
necessary. A CHANGE ENGINE OIL message will
come on. Change your oil as soon as possible within
the next two times you stop for fuel. It is possible that, if
you are driving under the best conditions, the oil life
system may not indicate that an oil change is necessary
for over a year. However, your engine oil and ®lter
must be changed at least once a year and at this time
the system must be reset. Your dealer has GM-trained
service people who will perform this work using
genuine GM parts and reset the system. It is also
important to check your oil regularly and keep it at the
proper level.
If the system is ever reset accidentally, you must
change your oil at 3,000 miles (5 000 km) since your
last oil change. Remember to reset the oil life system
whenever the oil is changed.
5-14

*1Ð Gasoline Engine and Diesel Engine.
*2Ð Gasoline Engine; ECMRPV Ð Diesel Engine.
*3Ð Gasoline Engine; FUEL HT Ð Diesel Engine.
*4Ð Gasoline Engine; ECM I Ð Diesel Engine.
*5Ð IGN/EDU
Fuses Usage
GLOW PLUGDiesel Glow Plugs and Intake
Air Heater
CUST FEED Gasoline Accessory Power
STUD #1Auxiliary Power (Single
Battery and Diesels Only)/
Dual Battery (TP2) Do not
install fuse.
MBECMid Bussed Electrical Center
Power Feed, Front Seats,
Right Doors
BLOWER Front Climate Control Fan
LBECLeft Bussed Electrical
Center, Door Modules,
Door Locks, Auxiliary Power
Outlet Ð Rear Cargo Area
and Instrument Panel
Fuses Usage
STUD 2Accessory Power/Trailer
Wiring Brake Feed
ABS Anti-Lock Brakes
VSES/ECAS Vehicle Stability
IGN A Ignition Power
IGN B Ignition Power
LBEC 1Left Bussed Electrical Center,
Left Doors, Truck Body
Controller, Flasher Module
TRL PARK Parking Lamps Trailer Wiring
RR PARKRight Rear Parking and
Sidemarker Lamps
LR PARKLeft Rear Parking and
Sidemarker Lamps
PARK LP Parking Lamps Relay
STARTER Starter Relay
INTPARK Interior Lamps
STOP LP Stoplamps
5-111