- 2025–2027 Factory-verified
2025–2026: O on all trims; 2027: Preferred, Sport Touring: O; Avenir: S
ULM Factory-verified
Also documented for CadillacChevroletGMC
Documented applications
This page aggregates every documented appearance of ULM in the Buick reference. Confidence and citations are shown per application — the same code can be better documented in one year than another.