R8G Factory-verified

GMC · Regular Production Option

OnStar One Fleet, 12 months

Years 2025–27 Models 9 Factory citations 28

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Also described as OnStar One Fleet plan, 12 months

Also documented for Buick Cadillac Chevrolet

Documented applications

Acadia — Third generation (2024–2027)

2025–2027 Factory-verified

O on all trims; the 2025 list names it OnStar One Business Plus

GM factory document — 2025 gmc acadia fleet order guide, p.53.
GM factory document — 2026 gmc acadia fleet order guide, p.47.
GM factory document — 2027 gmc acadia fleet order guide, p.50.

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

2025–2027 Factory-verified

O on all trims; the 2025 list names it OnStar One Business Plus

GM factory document — 2025 gmc canyon fleet order guide, p.52.
GM factory document — 2026 gmc canyon fleet order guide, p.67.
GM factory document — 2027 gmc canyon fleet order guide, p.68.

Savana — GMT610 (2003–2027)

2025 Factory-verified

the 2025 guides name it OnStar One Business Plus, 12 months of service; O on all trims

GM factory document — 2025 gmc savana cargo fleet order guide, p.47.
GM factory document — 2025 gmc savana cutaway fleet order guide, p.61.
GM factory document — 2025 gmc savana passenger fleet order guide, p.38.

Sierra 1500 — Next-Generation (2027)

2027 Factory-verified

all trims: O

GM factory document — 2027 gmc next generation sierra 1500 retail and fleet fleet order guide, p.115.
GM factory document — 2027 gmc next generation sierra 1500 retail and fleet fleet order guide rpo codes, p.1.

Sierra HD — T1XX (2020–2027)

2025–2027 Factory-verified

the 2025 lists name it OnStar One Business Plus; Pro, SLE, SLT, AT4, AT4X, Denali, Denali Ultimate: O

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.121.
GM factory document — 2026 gmc sierra 2500 hd retail and fleet fleet order guide, p.115.
GM factory document — 2027 gmc sierra 2500 hd retail and fleet fleet order guide, p.109.

Sierra — T1XX (2019–2026)

2025–2026 Factory-verified

the 2025 list names it OnStar One Business Plus

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

O on all trims; fleet and government order types; the 2025 list names it OnStar One Business Plus

GM factory document — 2025 gmc next generation terrain fleet order guide, p.25.
GM factory document — 2026 gmc next generation terrain fleet order guide, p.32.
GM factory document — 2027 gmc terrain fleet order guide, p.33.

Yukon — T1XX (2021–2027)

2025–2027 Factory-verified

2027: O on all trims; the 2025 guide reads OnStar One Business Plus, 12 months of service

GM factory document — 2025 gmc new yukon denali fleet order guide, p.87.
GM factory document — 2026 gmc yukon denali fleet order guide, p.94.
GM factory document — 2027 gmc yukon fleet order guide, p.83.

Yukon XL — T1XX (2021–2027)

2025–2027 Factory-verified

2027: O on all trims; the 2025 guide reads OnStar One Business Plus, 12 months of service

GM factory document — 2025 gmc new yukon xl denali fleet order guide, p.93.
GM factory document — 2026 gmc yukon xl denali fleet order guide, p.94.
GM factory document — 2027 gmc yukon xl fleet order guide, p.85.

This page aggregates every documented appearance of R8G in the GMC reference. Confidence and citations are shown per application — the same code can be better documented in one year than another.