Introduction | Installation | Land Mines | Operation | Capability | Engine OBD | ABS OBD  

VAG-COM : OBD Capability on the S2

With the introduction of Bosch Motronic and MPI engine management systems on some VW/Audi vehicles in 1990, came improved diagnostic capability to verify the operating conditions of the engine and it's ECU. In dealerships, a hefty diagnostic tool known as the VAG1551 is used to hook up to the car via the 2x2 OBD connectors. Over time, additional electronic control modules such as ABS, Climate Control and many others, also took on the OBD functionality right across the VAG range. Much of this enhanced OBD coverage only applies to Audi's built from around 1996 so the S2 only has a subset of the OBD functions that work with the VAG1551 and VAG-COM.

For 3B engined cars, only the engine ECU can communicate with VAG-COM. The ABY and ADU engines have enhanced OBD capability. Only cars built for MY94 and later have an ABS controller with OBD functionality. If your car has the ABS cancel switch fitted as standard then it will NOT have the OBD functionality for the ABS.

UPDATE - The (optional) airbag controller used in the Audi S2 also has OBD functionality which works fine with VAG-COM. All you can really do of course is to check fault codes and some basic status info. Adventurous users may check or change the Airbags enabled/disabled status if they so wish, but this is best left to franchised dealerships for obvious reasons.

Data Groups

It is important to know how information is organised into the various groups and channels (or measurement blocks to use Audi's terminology) . A maximum of 256 data groups (numbered 000-255) are accessible by the OBD system on each controller. Fortunately only a small number of these groups are actually used by the controllers found in the S2.

Group 000 contains ten 'channels' which are used to store and display various parameters that are measured by the controller in question. More details on these can be found here for the Motronic ECU and here for the ABS controller .

Groups 001 - 255 are structured as four channels that can store and display parametric information. A subset of these groups is used on the Motronic ECU for the ABY & ADU engine, but not for the 3B. Click here for for more diagnostic info on the Motronic ECU.

Label Files

Please Note -

Whilst a good deal of VAG-COM functionality can be tested for "free", to verify it works on your particular combination of PC and car, it's worth knowing that Group 000 cannot be accessed on any controller in the car until the software package is fully activated i.e Paid for and registered !

This means you won't be able to read measurement blocks from the ABS controller, Airbag controller or 3B engine with the freeware VAG-COM download. However, you will be able to read fault codes and read data from controllers which use Groups 001-255. Check with the latest information at VAG-COM's home .