- 2006–2009 Factory-verified
2006 comes from the 2006 list (hummer/2006-hummer-h3-rpo-code-list.txt p.1), which prints A1 with the same wording as A31;
A31 Factory-verified
Also documented for BuickCadillacChevroletGMCOldsmobilePontiacSaturn
Documented applications
This page aggregates every documented appearance of A31 in the Hummer reference. Confidence and citations are shown per application — the same code can be better documented in one year than another.