Chevy VIN Number Codes  Checkdigit
The Chevy checkdigit is calculated from the other digits of a VIN and is used to
check for alteration. The example VIN Number, 1M8GDM9A?KP042788, may be to calculate the check digit value.
Transliteration comprises removing all of the letters from a Vehicle
Identification Number and substituting them with their appropriate numerical
counterparts. These numerical values can be found in the table below e.g. A =1.
Transliteration key: values for VIN Decoding
A: 1 
B: 2 
C: 3 
D: 4 
E: 5 
F: 6 
G: 7 
H: 8 
N/A 
J: 1 
K: 2 
L: 3 
M: 4 
N: 5 
N/A 
P: 7 
N/A 
R: 9 

S: 2 
T: 3 
U: 4 
V: 5 
W: 6 
X: 7 
Y: 8 
Z: 9 
The following is the weight factor for each position in the VIN. The 9th position
is that of the
check digit. It has been substituted with a 0, which will cancel
out in the multiplication step.
Position 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
11 
12 
13 
14 
15 
16 
17 
Weight 
8 
7 
6 
5 
4 
3 
2 
10 
0 
9 
8 
7 
6 
5 
4 
3 
2 
The following table shows how the products (=> Value x Weight) of a VIN may be calculated.
VIN 
1 
M 
8 
G 
D 
M 
9 
A 
? 
K 
P 
0 
4 
2 
7 
8 
8 
Value 
1 
4 
8 
7 
4 
4 
9 
1 
0 
2 
7 
0 
4 
2 
7 
8 
8 
Weight 
8 
7 
6 
5 
4 
3 
2 
10 
0 
9 
8 
7 
6 
5 
4 
3 
2 
Products 
8 
28 
48 
35 
16 
12 
18 
10 
0 
18 
56 
0 
24 
10 
28 
24 
16 
The products (8,28,48,35,16,12,18,10,0,18,56,0,24,10,28,24,16) are all added together to obtain a
Sum of 351
Check digit = Sum Mod 11