Keyless open

Years 2012, 2015–19, 2022–23, 2025–27 Models 10 Factory citations 25

Also described as Keyless OpenKeyless Open, extended range Remote Keyless EntryKeyless open, extended range, with keyless start (BTM) and automatic door lock and unlockE-Z Key passive entry system, extended range, with keyless start and automatic door lock and unlockE-Z Key passive entry system, extended range, automatic door lock and unlockKeyless entry, E-Z Key passive entry system, extended range, with keyless start and automatic door lock and unlock

Also documented for Cadillac Chevrolet GMC

Documented applications

Enclave — C1XX (2018–2024)

2018, 2022–2023 Factory-verified

S on all trims

GM factory document — 2018 buick enclave fleet order guide wayback, p.1.
GM factory document — 2022 buick enclave order guide copy nhtsa docket, p.4, p.20.
GM factory document — 2023 buick enclave order guide copy autoevolution wayback, p.4, p.19.

Enclave — VSS-S (2025–2027)

2025–2027 Factory-verified

S on all trims

GM factory document — 2025 buick all new enclave fleet order guide, p.3.
GM factory document — 2026 buick enclave fleet order guide, p.3.
GM factory document — 2027 buick enclave fleet order guide, p.3.

Encore — Gamma II (2013–2022)

2018–2019 Factory-verified

all trims: S

GM factory document — 2018 buick encore order guide copy gm authority, p.2, p.16.
GM factory document — 2019 buick encore order guide copy gm authority, p.2, p.14.

Encore GX — VSS-F (2020–2027)

2025–2027 Factory-verified

Preferred, Sport Touring, Avenir: S; includes extended range remote keyless entry

GM factory document — 2025 buick encore gx fleet order guide, p.3.
GM factory document — 2026 buick encore gx fleet order guide, p.3.
GM factory document — 2027 buick encore gx fleet order guide, p.3.

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

2016–2019 Factory-verified

all trims: S; the 2016 and 2017 guides call it E-Z Key passive entry

GM factory document — 2016 buick envision order guide copy gm authority, p.2, p.11.
GM factory document — 2017 buick envision order guide copy gm authority, p.2, p.13.
GM factory document — 2018 buick envision order guide copy gm authority, p.2, p.13.
GM factory document — 2019 buick envision order guide copy gm authority, p.2, p.14.

Envision — E2XX (2021–2027)

2025–2027 Factory-verified

2027: all trims: S

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.3.

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

2015 Factory-verified

2015: 1SL, 1SP, 1SR: S

GM factory document — 2015 buick lacrosse fleet order guide wayback, p.2.

Regal — E2XX (2018–2020)

2018–2019 Factory-verified

2019: all trims: S (2019 Sportback order guide)

GM factory document — 2018 buick regal sportback fleet order guide wayback, p.1.
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.3.

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

2012, 2016 Factory-verified

new for 2012 (GM's 2012 list); 2016: 1SN, 1SP, 1SX: S; with BTM keyless start

GM factory document — 2016 buick regal order guide copy gm authority, p.3, p.17.

Verano — Delta II (2012–2017)

2012, 2016 Factory-verified

2016: 1SL, 1ST: S; the keyless start is BTM; 2012: 1SL: S (GM 2012 ordering guide)

GM factory document — 2016 buick verano fleet order guide wayback, p.2.
GM factory document — 2012 buick verano online ordering guide copy gm authority, p.2.

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