111 problems have been reported for the 2005 Audi A6.
The following chart shows the 17 most common problems for 2005 Audi A6.
The number one most common problem is related to the vehicle's air bags
with 42 problems.
The second most common problem is related to the vehicle's electrical system
(15 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 2005 Audi A6 in the United States are 15,456 units [1]. If the total number of problems reported by Audi A6 owners in the last 14 years is 111, and the age of the vehicle is 14, the PPMY index can then be calculated as

The following chart shows the number of problems reported during each of the service
years since the debut of the 2005 Audi A6 in 2005.

Table 2. PPMY Index and Problem Occurrence Trend

Service Year

Number of Problems

2019

0

2018

5

2017

13

2016

27

2015

14

2014

5

2013

13

2012

7

2011

3

2010

4

2009

6

2008

2

2007

5

2006

4

2005

3

Compare the 2005 Audi A6 with Other Model Years

When making the decision between buying a new or used Audi A6,
the following table can be used to compare the 2005 Audi A6
with the Audi A6 from other model years.
Note that the number of problems reported for the 2005 A6 is 111
while the average number of problems reported for the 23 model years of the Audi A6 is 62.

Table 3. Compare the 2005 Audi A6 with other model years