2021 GMC Sierra 1500 Service and Repair Manual

2021 GMC Sierra 1500 service and repair manual — a detailed, factory-style reference for maintenance, diagnostics, and repair. Use it to confirm correct procedures, specifications, and system coverage before you start work.

Designed for technicians and DIY owners, this manual helps you troubleshoot accurately, follow step-by-step repair procedures, and reference wiring diagrams and system sections quickly while you work.

What’s included

• Step-by-step repair procedures and service information
• Specifications and reference data (where provided)
• Wiring diagrams and electrical sections
• Powertrain, brakes, steering, suspension, HVAC and more

Trims covered

• AT4 Crew Cab Pickup 4-Door
• Base Standard Cab Pickup 2-Door
• SLT Crew Cab Pickup 4-Door
• Base Extended Cab Pickup 4-Door
• Denali Crew Cab Pickup 4-Door
• SLE Crew Cab Pickup 4-Door
• Base Crew Cab Pickup 4-Door
• SLT Extended Cab Pickup 4-Door
• AT4 Extended Cab Pickup 4-Door
• SLE Extended Cab Pickup 4-Door
• Elevation Crew Cab Pickup 4-Door
• Elevation Extended Cab Pickup 4-Door

Engines covered

• 5.3L 5328CC 325Cu. In. V8 GAS OHV Naturally Aspirated
• 6.2L 6162CC 376Cu. In. V8 GAS OHV Naturally Aspirated
• 3.0L 2993CC 183Cu. In. l6 DIESEL DOHC Turbocharged
• 5.3L 5328CC 325Cu. In. V8 FLEX OHV Naturally Aspirated
• 4.3L 262Cu. In. V6 GAS OHV Naturally Aspirated
• 2.7L 2720CC 166Cu. In. l4 GAS DOHC Turbocharged

Index / Table of contents

• Body
• Brakes
• Chassis Electrical
• Driveline
• Engine Cooling
• Engine Electrical
• Engine Mechanical
• Engine Performance & Emission Controls
• Fuel System
• General Information & Identification
• Heating, Ventilation, & Air Conditioning
• Hybrid & Electric Vehicle Systems
• Steering
• Suspension
• Transmission, Clutch, & Transfer Case
• Wiring Diagrams