The most important number in a used car is not its price or fuel economy rating. It is its Vehicle Identification Number or VIN, as it is more commonly known. Reading used car vehicle identification numbers will help you know if the used car or truck you are buying has the equipment you think it does.

A disturbing story in the Kansas City Star said Enterprise Rent a Car sold used Chevy Impalas from 2006 to 2008 without standard driver side curtain air bags.

The air bags had been removed to save money at Enterprise’s request. The company, in its defense, said the vehicle identification numbers (VINs) reflected the fact that the Impalas did not have the side air bags but customers thought they did because Enterprise claims to have mistakenly advertised the Impalas as having the side airbags and Chevrolet does not sell the Impala without the airbags to the general public.

It’s important that you know how to read a VIN when buying your used car. It, unlike any other source, is the most valuable source of information for knowing when and where you used car was built and what kind of equipment it has.

How To Read a VIN

The vehicle identification number or VIN can be viewed through the lower right corner of the vehicle's windshield near the driver's door. Copy down the information from there on a piece of paper and you are good to go.

A VIN is basically a serial number for your car, truck or SUV. It is 17 characters long and is a mixture of numbers and letters.

It has four parts:

• World Manufacturer's Identification (WMI - three numbers or letters)
• Vehicle Description Section (VDS - five numbers or letters)
• The VIN Accuracy Check Digit (one number)
• Vehicle Identification Section (VIS - eight numbers or letters)

The First Three Characters

These numbers and letters are the manufacturer identification and tell you where the vehicle was built.

The First Character tells you where the vehicle was built. The U.S. is 1 or 4, Canada is 2, and Mexico is 3. Australia, New Zealand and some South American countries are also represented by numbers. Some of the more common countries are: Japan (J), Italy (Z), Germany (W) and Great Britain (S).

The Second Character will tell you the manufacturer while the Third Character identifies the kind of vehicle or the company’s manufacturing division.

The 4th to 8th Characters

This is the vehicle description series. It identifies the body style, powerplant, brakes, and the restraint system. The problem is different companies put the information in different places. With GM, for example, the restraint info is in the 7th character position, while BMW has the code in its 8th character position. By the way, if you’re buying a Chevy Impala and the 7th digit is a “0” your airbags have been deleted.

The 9th Character

This is something called a check digit. It verifies the previous 8 characters based on a mathematical computation developed by the U.S. Department of Transportation.

The 10th Character

This represents the year the car was built. Cars built before 1980 don’t have VINs, which is why the system starts in 1980. You will also notice the system does not use every letter in the alphabet. I, O, Q, U, and Z are omitted. The system are repeats itself every 30 years probably assuming most people could tell the difference between a 1980 and 2010 model.

• A: 1980
• B: 1981
• C: 1982
• D: 1983
• E: 1984
• F: 1985
• G: 1986
• H: 1987
• J: 1988
• K: 1989
• L: 1990
• M: 1991
• N: 1992
• P: 1993
• R: 1994
• S: 1995
• T: 1996
• V: 1997
• W: 1998
• X: 1999
• Y: 2000
• 1: 2001
• 2: 2002
• 3: 2003
• 4: 2004
• 5: 2005
• 6: 2006
• 7: 2007
• 8: 2008
• 9: 2009
• A: 2010
• B: 2011
• C: 2012
• D: 2013
• E: 2014
• F: 2015

The 11th Character

This tells you the plant where your car was built. Frankly, when buying a used car, this should not be a huge concern. Quality problems will have demonstrated themselves long before your purchase.

The 12th through 17th Characters

These are what most of us call the serial numbers of the car. Each manufacturer has a different system for what this means.

In the end, the best bet for understanding various components of a used vehicle’s VIN, is to go to a search engine and type in Understanding BMW VIN. It will take you to various sites that will help you further decipher the VIN.