YF5 Factory-verified

Buick · Regular Production Option

Certification, emission, California

Years 1987, 1989, 1998–02, 2005–09, 2014–19, 2022–23, 2025–27 Models 24 Factory citations 55

Also described as Emissions, California requirementsCalifornia emissionsEmissions, California state requirementsEmission system, California

Also documented for Cadillac Chevrolet GMC Hummer Oldsmobile Pontiac Saturn

Documented applications

Cascada — Delta II (2016–2019)

2016–2019 Factory-verified internal

; all trims: O

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.

Century — A-body (1982–1996)

1989 Single-source internal

the 1989 Celebrity order guide lists it as a must-order emissions choice (a shared A-body emissions code); no Century source names it, so the row rests on the kit page alone

GM Heritage factory kit — 1989 Chevrolet Celebrity, p.10.

Enclave — C1XX (2018–2024)

2018, 2022–2023 Factory-verified internal

; all trims: O; 2018: GM order guide via GM Authority

GM factory document — 2018 buick enclave order guide copy gm authority, p.10, p.23, p.38.
GM factory document — 2022 buick enclave order guide copy nhtsa docket, p.14, p.31.
GM factory document — 2023 buick enclave order guide copy autoevolution wayback, p.14, p.29.

Enclave — Lambda / GMT967 (2008–2017)

2008–2009 Factory-verified internal

GM factory document — 2008 buick enclave rpo code list, p.1.
GM factory document — 2009 buick enclave rpo code list, p.1.

Enclave — VSS-S (2025–2027)

2025–2027 Factory-verified internal

; O on all trims

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)

2014, 2018–2019 Factory-verified internal

; all trims: O

GM factory document — 2014 buick encore fleet order guide wayback, p.4.
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

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

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.20.
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.22.

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.11.

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.9.
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

GM factory document — 2017 buick lacrosse fleet order guide wayback, p.4.
GM factory document — 2018 buick lacrosse order guide copy gm authority, p.9.
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

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

LaCrosse — W-body / GMX365 (2005–2009)

2005–2009 Factory-verified internal

GM factory document — 2005 buick lacrosse rpo code list, p.1.
GM factory document — 2009 buick lacrosse rpo code list, p.1.

LeSabre — H-body (1992–1999)

1998–1999 Factory-verified internal

GM factory document — 1998 buick lesabre rpo code list, p.1.
GM factory document — 1999 buick lesabre rpo code list, p.1.

LeSabre — H-body (2000–2005)

2000–2002 Factory-verified internal

GM factory document — 2000 buick lesabre rpo code list, p.1.
GM factory document — 2002 buick lesabre rpo code list, p.1.

Lucerne — G-body (2006–2011)

2006–2009 Factory-verified internal

GM factory document — 2006 buick lucerne rpo code list, p.1.
GM factory document — 2009 buick lucerne rpo code list, p.1.

Park Avenue — G-body (1997–2005)

1998, 2000–2002 Factory-verified internal

GM factory document — 1998 buick park avenue rpo code list, p.1.
GM factory document — 2002 buick park avenue rpo code list, p.1.

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.14.

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

2016 Factory-verified internal

; 2016: all groups: O

GM factory document — 2016 buick regal order guide copy gm authority, p.11, p.24.

Regal — G-body (1983–1987)

1987 Confirmed internal

gnttype.org's 1987 option sheet

Rendezvous — U-body / GMT257 (2002–2007)

2006–2007 Factory-verified internal

GM factory document — 2006 buick rendezvous awd rpo code list, p.1.
GM factory document — 2007 buick rendezvous fwd rpo code list, p.1.

Riviera — G-body (1995–1999)

1998 Factory-verified internal

GM factory document — 1998 buick riviera rpo code list, p.1.

Terraza — U-body / GMT201 (2005–2007)

2005–2007 Factory-verified internal

GM factory document — 2005 buick terraza rpo code list, p.1.
GM factory document — 2006 buick terraza rpo code list, p.1.
GM factory document — 2007 buick terraza rpo code list, p.1.

Verano — Delta II (2012–2017)

2016 Factory-verified internal

; 2016: all trims: O

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

This page aggregates every documented appearance of YF5 in the Buick reference. Confidence and citations are shown per application — the same code can be better documented in one year than another.