Car information

Common Diagnostic Procedures

Updated  23 May 2018

These pages detail some common vehicle-specific procedures that can be performed with VCDS. These are not a substitute for the correct Factory Repair Manual for your vehicle. Ross-Tech is not responsible for any damage or problems that may result from following these instructions. They are to be used at your own risk. We will be adding more pages periodically and welcome any comments or suggestions to

Ross-Tech Wiki – This is an encyclopedia of information such as common Fault Codes and Diagnostic Procedures. (Beta – This site is continually having content added and will eventually be the primary resource for information on usage of VCDS)
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Application Charts showing Which Interface works with each vehicle
(Which controllers are in my car and where do I find the diagnostic port?)

Possible DLC Locations

Some useful off-site links

Some excellent Excel spreadsheets that use data from VCDS (thanks to ). Right-click, save-as:

Stoney’s Audi A6 FAQAll sorts of AudiWorld threads about diagnostics.

Paul Waterloo’s AudiPages Audi A8 Transmission Coding Page
Transmission recoding for sportier performance.

The “Butt Dyno" Spreadsheet
How to calculate wheel horsepower and torque from acceleration and deceleration data.

Shiftpoints Analysis Spreadsheet
How to determine shiftpoints for optimal acceleration.

Freeware screen printing utility

A great thread on using VAG-COM to permanently alter Audi Allroad suspension height. This is also known as the 402 Mod.