131 problems have been reported for the 2001 Audi A4. The following chart shows the 19 most common problems for 2001 Audi A4. The number one most common problem is related to the vehicle's electrical system with 35 problems. The second most common problem is related to the vehicle's engine and engine cooling (30 problems).
In our research we use the PPMY index to compare the reliability of vehicles. The PPMY index of a certain model is defined as the problems reported per thousand vehicles per Year. The total sales of the 2001 Audi A4 in the United States are 43,015 units [1]. If the total number of problems reported by Audi A4 owners in the last 25 years is 131, and the age of the vehicle is 25, the PPMY index can then be calculated as
PPMY Index = 131 / 43,015 / 25 * 1000 = 0.12.
For more information, refer to this page: A study of reliability comparison across Audi A4 model year vehicles.
The following chart shows the number of problems reported during each of the service years since the debut of the 2001 Audi A4 in 2001.
| Service Year | Number of Problems |
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When making the decision between buying a new or used Audi A4, the following table can be used to compare the 2001 Audi A4 with the Audi A4 from other model years. Note that the number of problems reported for the 2001 A4 is 131 while the average number of problems reported for the 29 model years of the Audi A4 is 126.