GM Service Manual Online
For 1990-2009 cars only

Position

Vin Code

Vin Code Description

1

6

Divison

2

X

Model Year

3

U

Plant of Manufacture

4-9

800001

Sequence Number

All engines and transmissions are stamped with a partial Vehicle Identification Number (VIN), which is derived from the complete VIN. A VIN derivative contains the following nine positions:

    • Position 1 is the GM division identifier:
        6 = Cadillac
    • Position 2 is the model year:
        X = 1999
    • Position 3 is the assembly plant code:
        U = Hamtramck MI.
    • Positions 4-9 contain the assembly plant sequential number for the vehicle.
        A VIN derivative can be used to determine if a vehicle contains the original engine or transmission, by matching the VIN derivative positions to their accompanying positions in the complete VIN:
    • VIN derivative position 1 = VIN position 3
    • VIN derivative position 2 = VIN position 10
    • VIN derivative position 3 = VIN position 11
    • VIN derivative positions 4-9 = VIN positions 12-17