- 2015–2017, 2019, 2021–2022 Factory-verified
2015–2016, 2021: S on all trims; the upfitter lists mark it do not use after 2009 major programs
T3C Factory-verified
Also documented for Chevrolet
Documented applications
This page aggregates every documented appearance of T3C in the GMC reference. Confidence and citations are shown per application — the same code can be better documented in one year than another.