
Fuses Usage
4WDFour-Wheel Drive System,
Auxiliary Battery
HTR A/C Climate Control System
LOCK (Relay)Power Door Lock Relay
(Lock Function)
HVAC 1 Climate Control System
L DOORDriver’s Door Harness
Connection
CRUISECruise Control, Power Take
Off (PTO)
UNLOCK (Relay)Power Door Lock Relay
(Unlock Function)
RR FOG LP Not Used
BRAKE Anti-Lock Brake System
DRIVER UNLOCKPower Door Lock Relay
(Driver’s Door Unlock
Function)
IGN 0 TCM
TBC IGN 0 Truck Body Controller
VEH CHMSLVehicle and Trailer High
Mounted StoplampFuses Usage
LT TRLR ST/TRN Left Turn Signal/Stop Trailer
LT TRNLeft Turn Signals and
Sidemarkers
VEH STOPVehicle Stoplamps, Brake
Module, Electronic Throttle
Control Module
RT TRLR ST/TRN Right Turn Signal/Stop Trailer
RT TRNRight Turn Signals and
Sidemarkers
BODY Harness Connector
DDM Driver Door Module
AUX PWR 2 Not Used
LOCKS Power Door Lock System
ECC Not Used
TBC 2C Truck Body Controller
FLASH Flasher Module
CB LT DOORSLeft Power Windows Circuit
Breaker
TBC 2B Truck Body Controller
TBC 2A Truck Body Controller
5-93
2003 - Sierra Denali

Fuses Usage
FOG LP Fog Lamp Relay
FOG LP Fog Lamps
HORN Horn Relay
W/S WASHWindshield Washer Pump
Relay
W/S WASH Windshield Washer Pump
INFOOnStar/Rear Seat
EntertainmentFuses Usage
RADIO AMP Radio Amplifier
RH HID Not Used
HORN Horn
EAP Not Used
TREC All-Wheel Drive Module
SBA Supplemental Brake Assist
Capacities and Specifications
Capacities and Specifications
ApplicationCapacities
English Metric
Cooling System 14.8 quarts 14.0 L
Engine Oil with Filter 6.0 quarts 5.7 L
Fuel Tank 26.0 gallons 98.4 L
Air Conditioning Refrigerant R134a 1.6 lbs. 0.7 kg
Use Refrigerant Oil, R134a Systems
All capacities are approximate. When adding, be sure tofill to the approximate level, as recommended in this
manual. SeePart D: Recommended Fluids and Lubricants on page 6-15.
5-99
2003 - Sierra Denali

Engine Specifications
Engine VIN Code Type Spark Plug Gap
VORTEC™6000 U V8 0.060 inches (1.52 mm)
Wheels and Tires
Wheel Nut Torque 140 lb ft (190Y)
Tire Pressure See the Certification/Tire label on the rear edge of the
driver’s door.
Normal Maintenance
Replacement Parts
Part Number
Oil Filter*PF44
Engine Air Cleaner/Filter* A1518C
Passenger Compartment Air Filter Kit** 52485513
PCV Valve*CV2001–C
Spark Plugs41–974*/PZTR5A15 NGK
Fuel Filter*GF626
Wiper Blades**15153642
TypeITTA
*ACDelco
®Part No.
**GM Part No.
5-100
2003 - Sierra Denali

Maintenance Schedule......................................6-2
Introduction...................................................6-2
Your Vehicle and the Environment....................6-2
Maintenance Requirements..............................6-2
How This Section is Organized.........................6-3
Part A: Scheduled Maintenance Services...........6-4
Using Your Maintenance Schedule....................6-4
Scheduled Maintenance...................................6-5
Part B: Owner Checks and Services................6-10
At Each Fuel Fill..........................................6-10
At Least Once a Month.................................6-10
At Least Twice a Year...................................6-10At Least Once a Year
...................................6-11
Part C: Periodic Maintenance Inspections
.........6-14
Steering and Suspension Inspection
................6-14
Exhaust System Inspection
............................6-14
Fuel System Inspection
..................................6-14
Engine Cooling System Inspection
...................6-14
Transfer Case and Front Axle (All-Wheel
Drive) Inspection
.......................................6-15
Brake System Inspection
................................6-15
Part D: Recommended Fluids and Lubricants
. . . .6-15
Part E: Maintenance Record
...........................6-17
Section 6 Maintenance Schedule
6-1
2003 - Sierra Denali

Part A: Scheduled Maintenance
Services
This part contains engine oil and chassis lubrication
scheduled maintenance which explains the engine oil life
system and how it indicates when to change the
engine oil andfilter. Lubricate chassis components with
each oil change. Also, listed are scheduled maintenance
services which are to be performed at the mileage
intervals specified.
Using Your Maintenance Schedule
We at General Motors want to help you keep your
vehicle in good condition. But we don’t know exactly how
you’ll drive it. You may drive very short distances only
a few times a week. Or you may drive long distances in
very hot, dusty weather. You may use your vehicle in
making deliveries. Or you may drive it to work, to
do errands or in many other ways.
Because of all the different ways people use their
vehicles, maintenance needs vary. You may need more
frequent checks and replacements. So please read
the following and note how you drive. If you have any
questions on how to keep your vehicle in good condition,
see your dealer.This part tells you the maintenance services you should
have done and when to schedule them.
When you go to your dealer for your service needs,
you’ll know that GM-trained and supported service
people will perform the work using genuine GM parts.
The properfluids and lubricants to use are listed in
Part D. Make sure whoever services your vehicle uses
these. All parts should be replaced and all necessary
repairs done before you or anyone else drives the
vehicle.
This schedule is for vehicles that:•carry passengers and cargo within recommended
limits. You willfind these limits on your vehicle’s
Certification/Tire label. SeeLoading Your Vehicle on
page 4-47.
•are driven on reasonable road surfaces within legal
driving limits.
•are driven off-road in the recommended manner.
SeeOperating Your All-Wheel-Drive Vehicle Off
Paved Roads on page 4-18.
•use the recommended fuel. SeeGasoline Octane
on page 5-4.
6-4
2003 - Sierra Denali

Also look for any opened or broken air bag coverings,
and have them repaired or replaced. (The air bag
system does not need regular maintenance.)
Wiper Blade Check
Inspect wiper blades for wear or cracking. Replace
blade inserts that appear worn or damaged or that
streak or miss areas of the windshield. Also see
Cleaning the Outside of Your Vehicle on page 5-85.
Spare Tire Check
At least twice a year, after the monthly in ation check of
the spare tire determines that the spare is in ated to
the correct tire in ation pressure, make sure that
the spare tire is stored securely. Push, pull, and then try
to rotate or turn the tire. If it moves, use the wheel
wrench/ratchet to tighten the cable. SeeChanging a Flat
Tire on page 5-65.
Weatherstrip Lubrication
Silicone grease on weatherstrips will make them last
longer, seal better, and not stick or squeak. Apply
silicone grease with a clean cloth. During very cold,
damp weather more frequent application may be
required. SeePart D: Recommended Fluids and
Lubricants on page 6-15.
Automatic Transmission Check
Check the transmission uid level; add if needed. See
Automatic Transmission Fluid on page 5-20.A uid loss
may indicate a problem. Check the system and repair
if needed.
At Least Once a Year
Key Lock Cylinders Service
Lubricate the key lock cylinders with the lubricant
speci ed in Part D.
Body Lubrication Service
Lubricate all body door hinges, hood latch assembly,
secondary latch, pivots, spring anchor, release
pawl, tailgate hinge, tailgate linkage, tailgate handle
pivot points, latch bolt, fuel door hinge, locks and folding
seat hardware. Part D tells you what to use. More
frequent lubrication may be required when exposed to a
corrosive environment.
6-11
2003 - Sierra Denali