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Ross-Tech Wiki Pages is an online resource for detailed diagnostic procedures.

Below are common diagnostic procedures.

Automatic Transmission Info for VW/Audi
Xenon (HID) Headlamp Aiming
ESP Steering Angle Sensor Calibration
ESP Controller Coding
Suspension Level Control Calibration
Fuel Trim Information
Remote Control Matching
1.8T VAG-COM Info
Audi Service Interval Reminders SRI
VW Service Interval Reminders SRI
Throttle Body Alignment TBA
ABS Brake Pump Bleeding
Airbag Controller Coding


VAG-COM will work with most Volkswagen and Audi models sold World-Wide 1994 through 20010. It will work with some cars all the way back to model year 1990. It will also work with most late-model SEAT, and Skoda models sold in markets other than North America. If your VW or Audi has a 16-pin "OBD-II style" Data Link Connector, VAG-COM will definitely work. If your car has the old "2x2" Data Link Connection, check if there is a wire going to each pin, as shown in the picture. If there are four wires, VAG-COM should work. If there are only three, it won't. Please see these Application Charts where you can select your model and see which modules can communicate with VAG-COM. Also see the Issues page for a few things that may not work as expected. If in doubt, e-mail us.

Yes. If it doesn't work in a "chipped" car, the chip-vendor did something seriously wrong! Chips from reputable vendors do not interfere with diagnostic functions.

VAG-COM is a software program that turns your PC into a sophisticated VW/Audi diagnostic tool, which performs the functions as the VW/Audi dealers' own tools. Please see the Function Chart for the current feature set.

A computer running Microsoft Windows. A Laptop, Netbook or Tablet computer is best, but a desktop PC can also be used.

With a Serial interface: We recommend at least a 100 MHz Pentium (or AMD equivalent) with 32 MB of RAM and Windows 98 or newer. Windows 98, ME, 2000, XP, and Vista are all fine. As of version 8xx, we no longer support Windows 95 or NT4.

With a USB interface: We recommend at least a 500 MHz Pentium-3 (or AMD equivalent) with 64MB of RAM and Windows 98 or newer. USB interface work best with Windows XP or newer on a 1 GHz or faster PC, or on Vista on a machine robust enough to support that that operating system. USB interfaces will not work at all with Windows 95 or NT4.

VAG-COM may work on some lesser PC's, but anything less than the above recommendations are "unsupported" meaning if it doesn't work, please don't ask us for help.

Available disk-space should be a non-issue; VAG-COM requires less than 25 MB.
Screen resolution can be as low as 640x480.

If you are using a power supply for a laptop, it should be one specifically designed for that purpose, NOT a "universal" adapter.

Systems running Windows in a virtualized environment (for example Virtual PC on a Mac) are not supported. See also Question 1.8.

This depends primarily on the PC you're planning to use:
If you're using a modern PC running Windows XP or newer, then you should probably get a USB interface. Although USB interfaces are no faster than serial versions, it's becoming increasingly difficult to find new PC's with serial ports, so a USB interface is more future-proof.
If you're using a PC running an older version of Windows or with a CPU speed of less than 1GHz, we recommend a Serial interface.
Obviously a serial interface requires a Serial Port which looks like this:
Observe the port we surrounded with the GREEN oval. Notice the 9 male pins? That's a Serial port.   Observe the port circled and crossed in RED.  Notice the 15 female pins? That is a Monitor port and will not work!
USB<->Serial converters are often unable to handle the baud rate and timing requirements that are demanded by many control modules using the VAG protocols. We have had very poor results with most available USB<->RS-232 converters, therefore USB<->Serial converters are "Not Supported."  Please do not ask us for technical assistance if you are using one of these converters.   
If you want to use one of our Serial interfaces on a PC that doesn't have a serial port, we recommend you buy this Quatech SSP-100 PCMCIA-Card.  We don't sell them, but we've had excellent results with them.    We've got installation and configuration notes here.

Except for the Pro-Kit, our software is provided to you via our download page, rather than on floppy disks or CD's, so you will need a way to transfer the Self-Installing EXE file to the PC that you will be using with VAG-COM. The file fits easily on a removable USB drive and can also be burned onto a CD-R or CD-RW. Make sure that you do not run the EXE file until you have copied it onto the PC where you would like VAG-COM to be installed. You do not need to be connected to the Internet while using VAG-COM.

Yes, but you will probably need an extension cable for your interface.
We stock Serial extension cables 15' (3m) length. You can extend a Serial interface up to 50'. See the Accessories section of our Store for pricing.
We now also stock a 16-ft Active USB Extension. You can extend a USB interface up to 30' with two of these. We do not sell or support any other brands or models of USB extensions. if you have problems with a different brand of USB extension, the first thing we're going to tell you is to eliminate the extension.

There will be no "native" Mac or Linux versions.  The time and effort required to "port" VAG-COM to these platforms would never be worthwhile.
One person has gotten VAG-COM running under Linux using WINE -- click here for details.
A much more recent one:  HOW-TO Install VAG-COM in Ubuntu Linux using Wine
Mac (IBM/Motorola):
Results on IBM/Motorola Power-PC based Macs using Virtual PC vary.  Some people have gotten it to work, but sample rates tend to be poor and the sessions tend to drop frequently.   This is likely inherent in the overhead and latency inherent in the virtualized environment.    Some people have not gotten it to work at all.
Mac (Intel):
Reports from numerous users indicate that VAG-COM works perfectly on the latest Intel-based Macs when these run Windows XP natively using Boot Camp.    We've had a few reports that VAG-COM does not work with Windows Vista under Boot Camp.    Reports from people using Parallels are less favorable, most people who've tried this have not been able to get it to work at all, especially with Parallels builds lower than 3120.
The bottom line:
We do not consider any of these to be "Supported" platforms for VAG-COM.   If you can get VAG-COM to work on one of these platforms, great.   But if it doesn't work, please don't expect us to be able to help you.

Possibly at some point in the future, but we don't have a timetable yet. We conducted a poll of current and potential VAG-COM users about where we should concentrate development efforts. The results:
75 % Improving and adding features to the Windows version
11 % Porting VAG-COM to Windows CE / PocketPC
9 % Porting VAG-COM to Palm
3 % Porting VAG-COM to LINUX
2 % Porting VAG-COM to Macintosh
Some of our customers use VAG-COM on a tablet PC such as a Fujitsu Stylistic or on an ultra-portable PC such as a Toshiba Libretto. These can be purchased inexpensively on auction sites. These REAL PC's work wonderfully and have very small form factors (the Libretto is about the size of a VHS video cassette).

OBD-II is a government mandated diagnostic protocol that is primarily aimed at diagnosing emissions-related problems.   An OBD-II scan tool will work in many different brands of cars.  VAG-COM uses VW's proprietary diagnostic protocol and will only work in VW/Audi vehicles.  Although you can use an OBD-II Scan Tool in an OBD-II compliant (1996 or newer) VW or Audi, an OBD-II Scan Tool can only talk to the engine, not the numerous other "intelligent" systems in the car.   Want to reprogram your central locks or your Radio?  Diagnose a problem with your ABS, Airbags, or Automatic Transmission?  Re-align your Immobilizer after swapping ECU's?  Reset your Service Reminder Indicators?   Communicate with a pre-1996 model (not OBD-II compliant) car?  An OBD-II Scan-Tool can't do any of these things. Please see our OBD-II Page for information on using the Generic OBD-II function in our Interface. Want some reasons to choose VAG-COM over a generic OBD-II scan tool? See this Real World Comparison.
Our latest version of VAG-COM adds Generic OBD-II functionality, see the Download Page for more info.

No. A brand new instrument cluster (with less than 100 km on it) can be rolled forward, one time only. Of course, this assumes that the instrument cluster is "diagnostics capable". Not all instrument clusters with electronic odometers are.

No, we have investigated flashing, but found that there are several different methods of encryption for various VW/Audi vehicles, as well as delicate licensing issues to overcome. Therefore, we do not intend to pursue flashing any further at this time. You cannot alter boost, timing, fueling, rev limiter, or speed limiter with VAG-COM. You should contact a chiptuner if you wish to have those parameters altered.

Yes.  A good Repair Manual containing the the "Native" Scan-Tool procedures for your car.   VCDS is a tool, not an on-line service manual. We could not possibly document everything you can do with it in every year and model of VW/Audi that VAG-COM can be used with.
For US and Canadian VW and Audi models, the best source are the Repair Manuals by Robert Bentley Publishers.    Please note that Bentley also has some publications called "Service Manuals".   These tend to be less complete than the Official Factory Repair manuals and are not recommended for use with VAG-COM.
In the USA, VW/Audi provides online fee-based factory repair information through the following sites:
Since the above sources of repair information only applies to US/Canadian vehicles, if your car is European-spec or from the rest of the World, they may be of little use to you.
For Rest-of-World VW, Audi, and SEAT manuals, check
For Rest-of-World Skoda manuals, check

Yes, we began testing on Vista in December of 2006 and the current VCDS Release version fully supports Vista (both Vista-32 and Vista-64) with a Vista-aware installer and appropriately signed USB drivers.   VCDS can be downloaded here.
We will not support any older versions of VAG-COM on Windows Vista.    If you get a new PC with Vista already on it, or if you upgrade an existing PC to Windows Vista, we recommend using a current version.  Since 3rd party interfaces only work with older versions of VAG-COM, we do not support the use of them with Vista even if you have previously registered the software.
All interfaces sold by Ross-Tech since February of 2004 are compatible with the current version as are many that we sold before then.    If you have an older Ross-Tech interface or if you are a registered user with a 3rd-party interface, upgrades are available here.

Again, we consider the combination of an old version of VAG-COM and Windows Vista to be "unsupported".  However some people have reported success with various combinations of the following:
- Do not install in the \Program Files\ tree.   Instead, install in C:\Ross-Tech\VAG-COM\
- Make sure you user account has full Read/Write rights to the folder you've installed in.
- Use "Run this program in compatibility mode for: Windows XP (SP2)"
- Use "Run this program as an administrator"
If none of that works for you, then we have no additional advice other than to use a current version.

Yes,  the current VCDS Release version fully supports Windows 7 (both 32 and 64 bit versions) .
Everything stated in the previous two questions about Windows Vista also applies to Windows 7.   However, there is one caveat:
- If you have a genuine Ross-Tech interface which is compatible with current VCDS versions,
you should use the latest Release. We introduced a Windows-7 aware installer starting with Beta 904.




- USB connector plugs into most modern laptops! (USB 1.1 or 2.0)

- 12 Months Hardware Warranty

- 8GB USB Drive with Latest Software + User Manual

- Free Shipping

- Fully backwards compatible with older cars using a single K-line or K plus L.

Extra Features

This interface comes with an OBD-II type connector which plugs right in to most 1994 and newer VW’s and 1996 and newer Audis.   Most 1990-1995 Audis and 1990-1993 VW’s have the “2×2” data link connector, click here for more info.


This interface works with all diagnostic-capable VW, Audi, Seat, and Skoda models from 1990 through 2015.
It does NOT fully support the following vehicles:

  1. 2016+ Audi Q7 (Rest-of-World) Chassis 4M (2017+ North American Region chassis F7)
  2. 2016+ Audi A4 B9 (Rest-of-World) chassis 8W (2017+ North American Region chassis F4).
  3. 2017+ models (including all MQB-A0 cars such as the SEAT Ibiza KJ)

Computer Requirements

We recommend at least a 1 GHz Pentium-3 (or AMD equivalent) with 128 MB of RAM and Windows XP or newer.  Windows Vista, 7, 8. 8.1, or 10 on a machine robust enough to support the respective operating system are also fine.  As of version 10.6, we no longer support Windows 95, 98, ME or NT4. If you’re using a PC that has a CPU speed less than 1 GHz and which has a Serial port, then you should consider the Serial HEX-COM+CAN instead.

VCDS Pro Kit


With our new HEX-NET Pro interface, this kit includes everything the busy shop needs to perform powerful diagnostic analysis for VW, Audi, Seat, or Skoda automobiles. The HEX-NET Pro communicates with VCDS by wireless WiFi or by wired USB, turning a Windows® PC into a factory level diagnostic tool for VAG Brands. Also, at no additional cost, embedded in the HEX-NET is our new VCDS-Mobile® software* which enables most smart devices with WiFi and a web browser to perform VCDS like diagnostics on non-PC devices. Our Pro-kits include a handy carrying case to store all the items needed including: (

- HEX-NET Pro USB Wire w/Locking Screw

- USB Flash Drive w/VCDS program

VCDS Promo Kit

VCDS Promo Kit

Everything a busy shop needs to turn any PC / Laptop with an available USB port into a powerful diagnostic tool for VW, AUDI, SEAT, SKODA vehicles. The VCDS PROMO-KIT includes the following..

- VCDS HEX+USB+CAN Interface,

- Full Licence + Fully Registered + Unlimited VINs

- Lifetime Tech Support

- 12 Months Hardware Warranty

- 8GB USB Drive with Latest Software + User Manual

- Free Shipping