2021 GMC Sierra 1500 Service and Repair Manual

This factory service and repair manual for the 2021 GMC Sierra 1500 keeps five engines in service, the 3.0L turbocharged inline-six diesel, the turbocharged 2.7L inline-four, and the naturally aspirated 5.3L and 6.2L V8s and 4.3L V6, across Base, AT4, Denali, Elevation, SLE and SLT trims in three cab lengths. Diesel and gasoline work diverge sharply on this truck, and the manual separates the specifications, torque values, wiring diagrams and diagnostics to match.

Engines covered

• 5.3L V8 (325 cu in) — OHV, naturally aspirated, gasoline or flex-fuel
• 6.2L V8 (376 cu in) — OHV, naturally aspirated, gasoline
• 3.0L inline-six (183 cu in) — DOHC, turbocharged, diesel
• 4.3L V6 (262 cu in) — OHV, naturally aspirated, gasoline
• 2.7L inline-four (166 cu in) — DOHC, turbocharged, gasoline

Body styles covered

• 4-door crew cab pickup
• 2-door standard cab pickup
• 4-door extended cab pickup

Trims covered

• Base
• AT4
• Denali
• Elevation
• SLE
• SLT

Known issues on the 2021 Sierra 1500. The federal record carries seven recalls. Two of them concern a transmission control valve that can fail and lock the rear wheels, one covering trucks whose earlier repair was performed incorrectly. Another describes connecting rod and crankshaft manufacturing defects in the 6.2L V8 that can damage the engine to the point of failure. Seat belts appear twice more, once for brackets not secured to the front-row center seat frame and once for incorrect fastening bolts. Complaints reach 551: 195 engine, 130 power train, 54 electrical system.