T8Z Factory-verified

GMC · Regular Production Option

Buckle to Drive

Years 2004, 2022–27 Models 13 Factory citations 44

Query this via API →

Also described as Buckle to driveSeat belt shifter interlock, customizableEmissions, Mexico low emission vehicle

Also documented for Buick Cadillac Chevrolet

Documented applications

Acadia — Third generation (2024–2027)

2025–2027 Factory-verified

S on all trims; keeps the vehicle in Park until the driver seat belt is fastened; times out after 20 seconds

GM factory document — 2025 gmc acadia fleet order guide, p.3.
GM factory document — 2026 gmc acadia fleet order guide, p.2.
GM factory document — 2027 gmc acadia fleet order guide, p.3.

Canyon — Third generation (VSS-T) (2023–2027)

2023–2027 Factory-verified

S on all trims

GM factory document — 2023 gmc 23canyon electrical body builder 2023march13, p.12.
GM factory document — 2024 gmc canyon fleet order guide wayback, p.1.
GM factory document — 2025 gmc canyon fleet order guide, p.3.
GM factory document — 2026 gmc canyon fleet order guide, p.4.
GM factory document — 2027 gmc canyon fleet order guide, p.4.

Hummer EV Pickup (2022–2027)

2025–2026 Factory-verified

GM factory document — 2025 gmc hummer ev pickup fleet order guide rpo codes, p.1.
GM factory document — 2026 gmc hummer ev pickup fleet order guide rpo codes, p.1.

Hummer EV SUV — BT1 (2024–2027)

2025–2026 Factory-verified

GM factory document — 2025 gmc hummer ev suv fleet order guide, p.1.
GM factory document — 2026 gmc hummer ev suv fleet order guide, p.1.

Sierra EV — BT1 (2024–2027)

2025–2027 Factory-verified

GM factory document — 2025 gmc sierra ev denali fleet order guide rpo codes, p.1.
GM factory document — 2025 gmc sierra ev denali fleet order guide, p.1.
GM factory document — 2027 gmc sierra ev fleet order guide rpo codes, p.1.
GM factory document — 2027 gmc sierra ev fleet order guide, p.3.

Sierra 1500 — Next-Generation (2027)

2027 Factory-verified

all trims: S; prevents shifting out of Park until the driver seat belt is fastened; times out after 20 seconds; not available with T4Z

GM factory document — 2027 gmc next generation sierra 1500 retail and fleet fleet order guide, p.4.
GM factory document — 2027 gmc next generation sierra 1500 retail and fleet fleet order guide rpo codes, p.1.

Sierra — GMT800 (1999–2007)

2004 Factory-verified internal

GM factory document — 2004 gmc gmc c sierra 2wd rpo code list, p.1.

Sierra HD — GMT800 (2001–2007)

2004 Factory-verified internal

GM factory document — 2004 gmc gmc c sierra 2wd rpo code list, p.1.

Sierra HD — T1XX (2020–2027)

2024–2027 Factory-verified

2024: GM Authority 2024 changes page; Pro, SLE, SLT, AT4, AT4X, Denali, Denali Ultimate: included in the trim group

GM factory document — 2025 gmc sierra 2500 hd retail and fleet fleet order guide rpo codes, p.1.
GM factory document — 2026 gmc sierra 2500 hd retail and fleet fleet order guide rpo codes, p.1.
GM factory document — 2027 gmc sierra 2500 hd retail and fleet fleet order guide rpo codes, p.1.
GM factory document — 2025 gmc sierra 2500 hd retail and fleet fleet order guide, p.13.
GM factory document — 2026 gmc sierra 2500 hd retail and fleet fleet order guide, p.12.
GM factory document — 2027 gmc sierra 2500 hd retail and fleet fleet order guide, p.10.

Sierra — T1XX (2019–2026)

2023–2026 Factory-verified

the upfitter lists read "Seat belt safety system, shifter interlock, Gen 3, infotainment customizable"

GM factory document — 2023 gmc 23 sierra 1500 electrical body builder sm en us 2022oct12, p.14.
GM factory document — 2024 gmc 24 sierra 1500 sm electrical body builder esid 23dec12, p.16.
GM factory document — 2025 gmc my25 sierra 1500 electrical bbm, p.14.
GM factory document — 2025 gmc sierra 1500 retail and fleet fleet order guide rpo codes, p.1.
GM factory document — 2026 gmc sierra 1500 retail and fleet fleet order guide rpo codes, p.1.

Terrain — Third generation (2025–2027)

2025–2027 Factory-verified

S on all trims

GM factory document — 2025 gmc next generation terrain fleet order guide, p.2.
GM factory document — 2026 gmc next generation terrain fleet order guide, p.2.
GM factory document — 2027 gmc terrain fleet order guide, p.2.

Yukon — T1XX (2021–2027)

2022–2023, 2025–2027 Factory-verified

2027: S on all trims

GM factory document — 2022 gmc 22 yukon yukon xl electrical body builder sm u 2021oct13, p.12.
GM factory document — 2023 gmc 23 yukon yukon xl electrical body builder sm en us 092822, p.12.
GM factory document — 2025 gmc new yukon denali fleet order guide, p.7.
GM factory document — 2026 gmc yukon denali fleet order guide, p.8.
GM factory document — 2027 gmc yukon fleet order guide, p.7.

Yukon XL — T1XX (2021–2027)

2022–2023, 2025–2027 Factory-verified

2027: S on all trims

GM factory document — 2022 gmc 22 yukon yukon xl electrical body builder sm u 2021oct13, p.12.
GM factory document — 2023 gmc 23 yukon yukon xl electrical body builder sm en us 092822, p.12.
GM factory document — 2025 gmc new yukon xl denali fleet order guide, p.7.
GM factory document — 2026 gmc yukon xl denali fleet order guide, p.7.
GM factory document — 2027 gmc yukon xl fleet order guide, p.7.

This page aggregates every documented appearance of T8Z in the GMC reference. Confidence and citations are shown per application — the same code can be better documented in one year than another.