Audi TTweaker’s Guide

Audi TTweaker’s Guide. This guide is about tweaking and troubleshooting the original Audi TT, also known as mk.I. The information is snatched from various sources, mostly from Audi related forums on the Internet. Even tough the information is believed to be correct, it is provided with no warranty of any kind.

Audi TTweaker’s User Manual. The guide is divided into three parts. First part, Chapter 2, contains information how to troubleshoot common problems, and some general information. Second part, Chapter 3, contains instructions for tweaking various features. Third part, Chapter 4, is a collection of lists and tables, in an easily printable form.

Audi TTweaker’s. As most things in a car are nowadays controlled with diagnostics software and a computer, this guide is mostly about the tricks and tweaks that can be done purely with software. At the moment, no hardware mods are included, though some general information is provided.

This guide is not supposed to replace the workshop repair manual, but rather provide some often used information in easily accessible form. If you ever have read the repair manual, you probably appreciate it.

About VAG-COM
VAG-COM is the diagnostics software for the Volkswagen-Audi Group cars. It is a semi-free product from Ross-Tech, http://www.ross-tech.com/. All you need is a VAG-COM compatible OBD-II cable, and the free software from Ross-Tech web site.

The official VAG diagnostics software is called VAS 5051, but only a few people have access to it. Fortunately, VAG-COM can do all the tricks the official software can do, and even more. Further, all the instructions for VAS 5051 in the workshop repair manual can be directly applied to VAG-COM.

There are two versions of VAG-COM available on the Ross-Tech site. The latest version requires a dongled cable from Ross-Tech. It is pricey, but you will get a great piece of software bloaded with features, plus full support from Ross-Tech.

Audi Diagnostics Trouble Codes
A Diagnostic Trouble Code (DTC) is a fault code stored in the car’s computer system. DTCs can be retrieved with VW/Audi Factory Scan Tools such as the VAG 1551 or VAG 1552 through a diagnostics connector (OBD-II). Several aftermarket scan tools and computer programs, like VAG-COM, are also capable of retrieving this information in this factory mode. The factory mode also allows the scan tool to be used for system diagnostic functions and also parameter tweaking.

Some DTC information can also be retrieved in a generic mode. The generic mode is not as complete as the factory mode, but allows commercially available scan tools to be used simply to read DTCs. For example, MOT stations can use the generic mode to retrieve some basic information about the engine’s fundamental functions.

Audi Throttle Body Adaptation without VAG-COM
Throttle body adaptation (TBA) is a procedure used to calibrate the throttle body flap sensors. Sometimes it is confused with clearing the ECU adaptation tables. The only procedure to ensure the real throttle body adaptation is to enter VAG-COM basic settings block 060. However, the ECU usually does TBR after its power supply is cycled, i.e. the fuse has been pulled or the battery has been disconnected.

The reason for doing TBA is that some people have reported power loss after a long period of unspirited driving, as if the ECU were adapting to the driving style. Presumably the ECU has just lost the flap sensor calibration. However, if hesitation is caused by misguided (ignition or fueling) adaptation, full reset may be needed instead of TBA.

If you don’t have VAG-COM, or you actually want to reset the ECU for clearing all adaptation tables, you can just pull the ECU fuse, or disconnect the battery. Leave the power out for 5min to ensure all the power has been drained. Then reconnect, and turn on ignition, but DO NOT start the engine. Listen out for the clicking under the bonnet, which is usually over after a minute. Turn off ignition.