🏷️ Basic Information

Make:

GMC

Model:

Sierra 1500

Year:

2003

Body Style:

Full-size Pickup Truck

Generation:

GMT800 (Second Generation)

Platform Code:

GMT800

👋 Introduction

Market Position:

The 2003 GMC Sierra 1500 is a highly popular full-size pickup truck known for its capability, comfort, and versatility. It competes in a segment dominated by strong offerings from Ford (F-150) and Dodge (Ram 1500), as well as its Chevrolet Silverado sibling.

Competitive Analysis:

This manual serves the robust aftermarket for DIY mechanics and fleet maintenance for a widely sold vehicle. Its online, licensed format directly competes with traditional printed manuals and less official digital versions, offering convenience and factory-backed accuracy.

Key Features:

Officially licensed content, factory-derived information, comprehensive coverage, user-friendly digital interface, cross-platform compatibility, year-long access, cost savings for DIY repairs.

📋 Manual Details

Coverage Areas:

Engine, Drivetrain, Suspension, Steering, Brakes, HVAC, Electrical Systems, Body, Chassis, Diagnostic Trouble Codes (DTCs)

Page Count:

Extensive (specific number not provided, but described as comprehensive factory-derived data)

Manual Type:

Service and Repair Manual Software (Online)

Language:

English

Format:

Online, Web-based Software

📖 Manual Coverage

Systems Covered:

Engine Mechanical, Engine Performance (Fuel Injection, Ignition), Cooling System, Lubrication System, Exhaust System, Automatic Transmission, Manual Transmission, Transfer Case (4WD models), Drive Axles, Suspension (Front & Rear), Steering System, Power Steering, Brakes (Front & Rear, ABS), Fuel System, Emission Controls, HVAC System (Heating, Ventilation, Air Conditioning), Electrical System (Lighting, Instrumentation, Power Distribution), Starting & Charging System, Body & Chassis, Body Control Module (BCM), Wiring Diagrams, Diagnostic Procedures.

Procedures Included:

Routine Maintenance, Scheduled Maintenance, Troubleshooting, Diagnostic Procedures, Component Removal & Installation, Repair Procedures, System Adjustments, Wiring Harness Repair, Performance Tuning (basic diagnostics), Diagnostic Trouble Code (DTC) interpretation and resolution, Brake System Bleeding, Clutch Adjustment, Suspension Component replacement, Engine rebuild (overhaul), Transmission service and repair, HVAC system servicing and recharge.

Technical Depth:

Comprehensive, ranging from basic owner maintenance tasks to advanced diagnostic procedures and component-level repairs. Includes detailed diagrams, specifications, and step-by-step instructions derived from Original Equipment (OE) materials.

📊 Manual Specifications

Access Method:

Web browser based, requires internet connection.

Print Quality:

Digital rendering of factory-quality information.

Binding Type:

N/A (Digital Format)

Paper Type:

N/A (Digital Format)

Software Compatibility:

Compatible with PC, Laptop, Smartphone, Tablet via web browser.

Access Duration:

One (1) year subscription with options for renewal.

⚙️ Engine Specifications

Engine Options:

4.3L V6 (L35 Vortec 4300), 4.8L V8 (LR4 Vortec 4800), 5.3L V8 (LM7 Vortec 5300), 6.0L V8 (LQ4 Vortec 6000 - typically for HD models but availability may vary on 1500 series depending on configuration).

Engine Displacements:

4.3L (262 cu. in.), 4.8L (293 cu. in.), 5.3L (325 cu. in.), 6.0L (364 cu. in.)

2003 5.3L V8 Horsepower:

285 hp @ 5200 rpm (approximate)

2003 5.3L V8 Torque:

325 lb-ft @ 4000 rpm (approximate)

Fuel Injection Type:

Sequential Electronic Fuel Injection (SFI), Multi-Port Fuel Injection (MPFI)

Fuel Type:

Unleaded gasoline

🔧 Transmission

Standard Transmission:

4-speed Automatic (4L60-E, 4L80-E)

Optional Transmission:

5-speed Manual (NV3500, NV4500 for heavier duty configurations)

Transmission Features:

Electronic control, torque converter lock-up, available with 2WD and 4WD drivetrains. Transfer cases include NV246 (Autotrac) or NV243 (manual shift) for 4WD models.

📐 Dimensions

Wheelbase Options:

130.0 inches (Regular Cab, Extended Cab short bed), 143.5 inches (Extended Cab long bed, Crew Cab short bed)

Overall Length:

Varies by configuration, e.g., approx. 220.2 inches (Regular Cab short bed)

Overall Width:

Approx. 78.8 inches

Curb Weight:

Varies by configuration, typically 4,500 - 5,500 lbs

Gross Vehicle Weight Rating Gvw:

Typically 6,000 - 7,000 lbs for 1500 series

🛡️ Safety Features

NHTSA Rollover Rating:

4 out of 5 stars (for most configurations)

IIHS Front Offset Crash Test:

Good (for models with side airbags, if equipped).

Active Safety Features:

Available Anti-lock Braking System (ABS), Traction Control System (TCS) (often standard on higher trims or with certain powertrains).

Passive Safety Features:

Front airbags, available side-impact airbags, three-point seat belts, LATCH child seat anchors (rear seats).

💡 Technology Features

Infotainment System:

Standard AM/FM stereo with CD player, available premium audio systems, available navigation (rare for this year), rear seat entertainment (less common).

Driver Assistance Features:

Limited by modern standards. Primarily ABS and Traction Control. Cruise control.

Connectivity:

No integrated Bluetooth or USB ports. Auxiliary input for audio devices may be available on premium stereos.

🔧 Maintenance

Oil Change Interval:

Every 3,000-7,500 miles or 3-6 months, depending on oil type and driving conditions (refer to manual for specific recommendation based on oil used).

Tire Rotation Interval:

Every 5,000-7,500 miles.

Spark Plug Replacement Interval:

Varies by plug type: Platinum/Iridium plugs typically 100,000 miles; standard plugs 30,000-60,000 miles. Manual will specify.

Engine Oil Specification:

API Certified SAE 5W-30 Synthetic Blend or Full Synthetic for most engines (check specific engine and climate).

Engine Oil Capacity:

Approx. 4.5 - 6.0 quarts (4.2 - 5.7 Liters) depending on engine (5.3L typically ~6 quarts).

Transmission Fluid Type:

Dexron-III H (or equivalent Dexron-VI)

Transmission Fluid Capacity:

Approx. 4.5 - 6.5 quarts (dry fill) for automatic transmissions.

Coolant Specification:

GM P/N 12346290, Orange Concentrate (or equivalent orange long-life silicate-free).

Coolant Capacity:

Approx. 16-18 quarts (15.1-17.0 Liters).

Common Issues:

Catalytic converter failure, intake manifold gasket leaks (LS-based V8s), AFM/DOD issues (on later models or specific variants, less common on 2003), power steering pump leaks, dashboard cracking, HVAC blend door actuator failures, front hub bearing failure, transmission cooling line leaks.

Recall Information:

Check for recalls related to Takata airbags, ignition switch issues, or other safety campaigns specific to the 2003 model year.

📚 Vehicle History

Brand Heritage:

GMC (General Motors Truck Company) has a long-standing reputation for producing robust and capable trucks, often positioned as the premium or professional-grade division of General Motors.

Model Evolution:

The 2003 Sierra 1500 is part of the second generation (GMT800) of GM's full-size trucks, introduced for the 1999 model year. This generation brought significant styling updates, improved chassis dynamics, and powertrain enhancements over its predecessor.

Production Locations:

Fort Wayne, Indiana; Oshawa, Ontario, Canada; Pontiac, Michigan.

🏆 Awards & Recognition

Recognitions:

The GMT800 platform was generally well-received, often praised for its comfortable ride, capable powertrains, and refined interior for a truck of its era. Specific awards for the 2003 model year may vary but it consistently ranked high in consumer satisfaction surveys for full-size trucks.