Headlamps, halogen composite projector beam, blue translucent ring, flash-to-pass, automatic on and off, automatic delay and warning buzzer

Years 2012, 2014–19 Models 6 Factory citations 11

Also described as Headlamps, halogen composite projector beam, blue translucent ring, automatic exterior lamp controlHeadlamps, halogen composite, with automatic exterior lamp controlHeadlamps, halogen composite, flash-to-pass, automatic on and off, automatic delay, warning buzzerHeadlamps, halogen compositeHeadlamps, halogen composite, flash-to-pass, automatic on and off

Also documented for Chevrolet GMC

Documented applications

Encore — Gamma II (2013–2022)

2014 Factory-verified

all trims: S

GM factory document — 2014 buick encore fleet order guide wayback, p.3.

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

2016–2018 Factory-verified

2018: 1SV, 1SD, 1SL, 1SN: S

GM factory document — 2016 buick envision order guide copy gm authority, p.4, p.14.
GM factory document — 2017 buick envision order guide copy gm authority, p.5, p.18.
GM factory document — 2018 buick envision order guide copy gm authority, p.5, p.17.

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

2012, 2015 Factory-verified

2015: all groups: S; replaced TT4 for 2012 (GM Authority 2012 RPO list)

GM factory document — 2015 buick lacrosse fleet order guide wayback, p.3.

Regal — E2XX (2018–2020)

2018–2019 Factory-verified

2019: Regal, Preferred, Preferred II, Essence, GS: 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.5.

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

2012, 2016 Factory-verified

replaced TT4 for 2012 (GM's 2012 list); 2016: 1SV, 1SL, 1SN: S; adds automatic delay and warning buzzer

GM factory document — 2016 buick regal order guide copy gm authority, p.5, p.20.

Verano — Delta II (2012–2017)

2012, 2016 Factory-verified

2016: all trims: S; 2012: GM 2012 ordering guide, all trims: S

GM factory document — 2016 buick verano fleet order guide wayback, p.3.
GM factory document — 2012 buick verano online ordering guide copy gm authority, p.3.

This page aggregates every documented appearance of T4A in the Buick reference. Confidence and citations are shown per application — the same code can be better documented in one year than another.