VIN Decoder · GMC
GMC VIN Decoder: 1GT, 1GK, 2GT and 3GT Codes
Every GMC carries a North American VIN: the code starts 1, 2 or 3, and the check digit has to compute. The catch sits in position 11. A Z on a Sierra means Fort Wayne, Indiana; on an Acadia it means Spring Hill, Tennessee. A 1 is Wentzville on a Canyon and Oshawa on a Sierra Limited. On a GMC the plant letter only makes sense next to the model.
- WMI set: 6 codes, 1GT to 3GK
- Plant codes: 4 letters, two sources each
- Last verified: 8 October 2026
Decode a GMC VIN
Scope: GMC 1GT · 1GK · 2GT · 2GK · 3GT · 3GK0 / 17
GMC VINs leave out I, O and Q. On a Sierra's plate a ring-shaped character is always a zero.
What a GMC VIN actually tells you
GMC splits its codes by body type. T in third place means truck: 1GT for a Sierra, Canyon or Hummer EV Pickup built in the USA, 3GT for a Sierra from Silao in Mexico, 2GT for one from Oshawa in Canada. K means SUV: 1GK for the Yukon, Acadia and Hummer EV SUV, 2GK for the Terrain from CAMI in Ontario, 3GK for the Terrain from San Luis Potosí.
Characters four to eight describe model line, body and engine, and the ninth is the check digit. GM computes it on every GMC, since all of them carry North American VINs. We recomputed 63 real GMC numbers from model years 1995 to 2025, and none failed.
Character ten is the model year, eleven the assembly plant. Four letters point to the same plant on every GMC: R Arlington (Yukon), G Silao (Sierra), F Flint (Sierra HD) and U, the Detroit-Hamtramck site GM now calls Factory Zero, where the Hummer EV is built.
GMC WMI codes
| WMI | Meaning |
|---|---|
| 1GT | GMC, USA: trucks such as Sierra, Sierra HD, Canyon, Hummer EV Pickup |
| 1GK | GMC, USA: SUVs such as Yukon, Acadia, Hummer EV SUV |
| 2GT | GMC, Canada: trucks, e.g. the 2019 Sierra Limited from Oshawa |
| 2GK | GMC, Canada: SUVs, e.g. the Terrain from CAMI, Ingersoll |
| 3GT | GMC, Mexico: trucks, e.g. the Sierra from Silao |
| 3GK | GMC, Mexico: SUVs, e.g. the Terrain from San Luis Potosí |
Confirmed in NHTSA's vPIC register and in the Wikibooks GM tables; 1GT and 1GK also appear in the Kraftfahrt-Bundesamt list. 1GK belongs to GMC alone, since Cadillac's SUVs use 1GY and 3GY, so this page shares no code with Cadillac or Chevrolet.
Three countries, one rule: the GMC VIN
Looking at a Sierra or Yukon on a Polish, Norwegian or German plate? It was built in one of three countries, and the first character says which. The third tells truck from SUV. Position 11 is the one to read with care, because some of its letters change meaning from model to model.
USA: 1GT, 1GK
- Arlington (R) builds the Yukon and Yukon XL, Flint (F) the Sierra HD.
- The Hummer EV, pickup and SUV alike, comes from Factory Zero (U).
- Z and 1 depend on the model: Fort Wayne or Spring Hill, Wentzville or Oshawa.
Mexico: 3GT, 3GK
- 3GT with G in position 11 is a Sierra from Silao.
- 3GK is the Terrain from San Luis Potosí, which carries L as its plant letter.
- Mexican GMCs need a valid check digit exactly like American ones.
Canada: 2GT, 2GK
- 2GK is the Terrain built by CAMI in Ingersoll, Ontario, plant letter 6.
- 2GT shows up on the 2019 Sierra Limited from Oshawa, plant letter 1.
- Seen 2GK on an Acadia? Recheck it: every Acadia in our sample starts 1GK.
Same letter, two plants: Z, 1 and J
GM reuses position-11 letters across its plants, so on a GMC some of them change with the model. Z on a 2021 Sierra is Fort Wayne, on a 2017 Acadia Spring Hill. 1 on a Canyon is Wentzville, on a 2GT Sierra Limited Oshawa. J on a 2008 Acadia is Janesville, on a 2015 Acadia Lansing Delta Township. This page leaves those three letters unnamed rather than guess.
Green means the check digit adds up. A GMC that fails is shown red, because GM leaves position 9 to chance on none of these codes. Before you suspect fraud, look for the classic misreads on a dusty plate: S and 5, B and 8, Z and 2.
Model year: position 10 on a GMC
Every GMC stores its model year in position 10, and position 7 decides the 30-year cycle. 1GKS2HKJ has a letter there, so its L means 2020, not 1990. A 1990s Yukon such as 1GKEK13K has a digit in seventh place, so its S points to 1995. Bought a Sierra that was first registered in Germany in 2022? Its position 10 may still read 2019, because the registration date and the model year are two different things.
| Code | Model year | Code | Model year |
|---|---|---|---|
| A | 2010 | M | 2021 |
| B | 2011 | N | 2022 |
| C | 2012 | P | 2023 |
| D | 2013 | R | 2024 |
| E | 2014 | S | 2025 |
| F | 2015 | T | 2026 |
| G | 2016 | V | 2027 |
| H | 2017 | W | 2028 |
| J | 2018 | X | 2029 |
| K | 2019 | Y | 2030 |
| L | 2020 |
Frequently asked questions
What do the GMC WMI codes 1GT, 1GK, 3GT and 2GK mean?
1GT: GMC truck built in the USA (Sierra, Sierra HD, Canyon, Hummer EV Pickup). 1GK: GMC SUV from the USA (Yukon, Acadia, Hummer EV SUV). 2GT and 2GK are the Canadian codes, 3GT and 3GK the Mexican ones, found on Silao-built Sierras and on the Terrain.
Is the GMC Hummer EV a Hummer or a GMC?
A GMC. Its VIN starts 1GT for the pickup and 1GK for the SUV, and NHTSA's register decodes both as GMC, built at Factory Zero in Detroit. The H2 and H3 of the old Hummer brand use 5GR and 5GT, which belong to Hummer, not GMC, and this page reports them as another make.
Why must a GMC VIN pass the check digit?
Because every GMC code is issued for North America, where the ISO 3779 check digit in position 9 is mandatory. All 63 real GMC VINs we recomputed passed, from a 1995 Yukon to a 2025 Hummer EV SUV. A failure on a truck you're about to buy points to a slip of the keyboard, or to a number lifted from another truck.
Where is the VIN on a GMC?
Through the windscreen, bottom corner, driver's side: US rules require it to be readable from outside there. The door frame has its own label. German papers list it under E, a UK V5C among the vehicle details. Do all three match on the Sierra you're importing? If not, stop there.
What can't a GMC VIN tell you?
Trim level, colour and options are not in it. The VIN narrows the model line, body and engine; for the rest you need the dealer invoice or the build records. It holds no service history either.