NB9 Factory-verified

Buick · Regular Production Option

Emissions override, state-specific

Years 2015–19, 2022–23, 2025–27 Models 13 Factory citations 35

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Also documented for Cadillac Chevrolet GMC

Documented applications

Cascada — Delta II (2016–2019)

2016–2019 Factory-verified internal

; all trims: O; swaps YF5 and NE1 emissions between those states

GM factory document — 2016 buick cascada order guide copy gm authority, p.9.
GM factory document — 2017 buick cascada order guide copy gm authority, p.7, p.14.
GM factory document — 2018 buick cascada order guide copy gm authority, p.7, p.15.
GM factory document — 2019 buick cascada order guide copy gm authority, p.7, p.15.

Enclave — C1XX (2018–2024)

2018, 2022–2023 Factory-verified internal

; all trims: O; swaps YF5 and NE1 emissions between those states; 2018: GM order guide via GM Authority

GM factory document — 2018 buick enclave order guide copy gm authority, p.11, p.24, p.37.
GM factory document — 2022 buick enclave order guide copy nhtsa docket, p.15, p.32.
GM factory document — 2023 buick enclave order guide copy autoevolution wayback, p.14, p.30.

Enclave — VSS-S (2025–2027)

2025–2027 Factory-verified internal

; O on all trims; for dealers ordering in YF5 or NE1 states; the state list in the guide has Virginia in 2025 and New Mexico from 2026, and California is not named in 2027

GM factory document — 2025 buick all new enclave fleet order guide, p.13.
GM factory document — 2026 buick enclave fleet order guide, p.13.
GM factory document — 2027 buick enclave fleet order guide, p.14.

Encore — Gamma II (2013–2022)

2018–2019 Factory-verified internal

; for dealers in YF5 or NE1 emission states

GM factory document — 2018 buick encore order guide copy gm authority, p.22.
GM factory document — 2019 buick encore order guide copy gm authority, p.20.

Encore GX — VSS-F (2020–2027)

2025–2027 Factory-verified internal

; for dealers ordering vehicles in states that use the YF5 or NE1 emissions

GM factory document — 2025 buick encore gx fleet order guide, p.13.
GM factory document — 2026 buick encore gx fleet order guide, p.14.
GM factory document — 2027 buick encore gx fleet order guide, p.13.

Envision — D2XX, imported from China (2016–2020)

2016–2019 Factory-verified internal

; all trims: O; swaps YF5 and NE1 emissions between those states

GM factory document — 2016 buick envision order guide copy gm authority, p.16.
GM factory document — 2017 buick envision order guide copy gm authority, p.21.
GM factory document — 2018 buick envision order guide copy gm authority, p.19.
GM factory document — 2019 buick envision order guide copy gm authority, p.23.

Envision — E2XX (2021–2027)

2025–2027 Factory-verified internal

2027: all trims: O

GM factory document — 2025 buick envision fleet order guide rpo codes, p.1.
GM factory document — 2027 buick envision fleet order guide rpo codes, p.1.
GM factory document — 2027 buick envision fleet order guide, p.12.

Envista — VSS-F (2024–2027)

2025–2026 Factory-verified internal

; all trims: O

GM factory document — 2025 buick envista fleet order guide rpo codes, p.1.
GM factory document — 2025 buick envista fleet order guide, p.10.
GM factory document — 2026 buick envista fleet order guide rpo codes, p.1.
GM factory document — 2026 buick envista fleet order guide, p.10.

LaCrosse — E2XX, 3rd gen (2017–2019)

2017–2019 Factory-verified internal

; 2019: all trims: O; swaps YF5 and NE1 emissions between those states

GM factory document — 2017 buick lacrosse fleet order guide wayback, p.4.
GM factory document — 2018 buick lacrosse order guide copy gm authority, p.10.
GM factory document — 2019 buick lacrosse order guide copy gm authority, p.14.

LaCrosse — Epsilon II, 2nd gen (2010–2016)

2015 Factory-verified internal

; 2015: all groups: O; swaps YF5 and NE1 emissions between those states

GM factory document — 2015 buick lacrosse fleet order guide wayback, p.4.

Regal — E2XX (2018–2020)

2018–2019 Factory-verified internal

; 2019: Regal, Preferred, Preferred II, Essence, Avenir, GS: O (2019 Sportback order guide)

GM factory document — 2018 buick regal sportback fleet order guide wayback, p.1, p.5.
GM factory document — 2018 buick regal tourx fleet order guide wayback, p.1.
GM factory document — 2019 buick regal sportback order guide copy gm authority, p.15.

Regal — Epsilon II, 5th gen (2011–2017)

2016 Factory-verified internal

; 2016: all groups: O; swaps YF5 and NE1 emissions between those states

GM factory document — 2016 buick regal order guide copy gm authority, p.12, p.24.

Verano — Delta II (2012–2017)

2016 Factory-verified internal

; 2016: all trims: O; swaps YF5 and NE1 emissions between those states

GM factory document — 2016 buick verano fleet order guide wayback, p.4.

This page aggregates every documented appearance of NB9 in the Buick reference. Confidence and citations are shown per application — the same code can be better documented in one year than another.