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Chevy VIN Decoder
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