Why would I want a VAG-COM and WTF is it anyway?

[Ram®]

It is unquestionable that technology makes cars better, but as cars become more sophisticated, those who work on them must grow in sophistication as well. Modern cars, with their many electronic systems, require “electronic wrenches” to be repaired and modified. Generally, these electronic wrenches have been the domain of dealers and well funded repair shops. Though many new car dealers are excellent, most enthusiasts of any marque have accumulated enough bad experiences to make even the thought of going to one something to be avoided. And yet, if a trouble light comes on, the enthusiast has to take his vehicle to a dealer and pay for the service department to plug it into a computer and give him an estimate, indicating which parts the mechanic thinks needs replacement. This is an incredibly frustrating experience for owners who are capable of using conventional wrenches. Quite a few of us even own a computer, and it would seem to be a major improvement if we could plug our computers into our cars and learn what the dealer’s mechanic learns when he plugs in his. This is especially true for owners of vehicles no longer covered under the original manufacturers warranty.

The standard tool in a Volkswagen dealer’s service department is the VAG-1551 or VAG-1552 diagnostic tool. It is the dealers’ “electronic wrench,” and Volkswagen sells the tool only to its dealers. There are two alternatives for the enthusiast, however. VWTool/VDSPRO was one, but it was an early solution, primitive in today’s computing environment. It has not been supported for some time, though an update is planned soon. The other alternative is the Ross-Tech VAG-COM, a more recent development by Uwe Ross, a very talented computer engineer. Basically, Uwe Ross monitored the signals between a VAG-1552 and a car, reverse engineered them, and wrote a program that allows a PC to do everything a VAG-1552 can do, and more.

VAG-COM uses Volkswagen's proprietary diagnostic protocol and will only work in VW/Audi vehicles. In addition to showing fault codes and monitoring operating parameters, VAG-COM allows an enthusiast to make “adjustments,” such as reprogramming the locks or the stereo, re-aligning the immobilizer after swapping ECU’s and resetting service reminder indicators. VAG-COM can read any trouble codes in the vehicle, enabling one to diagnose a problem with the ABS, airbags or automatic transmission, and it can communicate with pre-1996 (non-OBD-II-compliant) cars. An OBD-II scan tool can’t do any of these things, and it costs more than VAG-COM, too.

There are some things the VAG-COM can’t do, such as “roll back” an electronic odometer, or “flash” the chip in the ECU with a new engine management program. VAG-COM can do things the VAG-1552 cannot. At this time, the most interesting “extra” is data logging, though due to slowness of communication between the ECU and PC, the sample rate is extremely limited. It would be useful for recording temperatures during a lapping session, for example, but less useful for monitoring a drag race. One caveat emphasized by Uwe Ross is that VAG-COM is a tool, not an on-line service manual. To make full use of VAG-COM, you will need a service manual containing the VAG-1551 Scan-Tool procedures for your car such as the Bentley Publishing manuals.

Some of the best paybacks for the tool is resetting Service Indicators for vehicles out of warranty and checking your car for errors before it goes to the main dealer for a service and seeing if they attend to them before you get your car back!

Best wishes,

Ram®

[Dave]

Excellent piece Ram... thanks [img]/ubbthreads/images/graemlins/laugh.gif[/img]

I have heard that vag.com has some data logging capabilities.. can this be used for track use and what sort of things does it log? For example, can it log top boost pressure?

Also.. what do I need in the way of computer.. laptop, windows 98 and what sort of cable-ing?

Cheers
Dave

[Ram®]

Hi Dave,

You can graph boost pressure as follows:

Go to Engine Measuring Block 011
Start Logging the data
In a high gear (4th/5th) give full throttle from 1500-2000 rpm to 3500-4000 rpm
Find and Open the Log file in Windows Explorer
In Excel graph actual/requested boost -vs- rpm
On a stock vehicle, one should see a spike at 2.1 bar quickly regulated at 1.9 through the whole rpm range



You only need a basic laptop which is cabable of running Windows '95 comfortably and which is equipped with a serial port 9-pin (d-type).

There are 5 packages available to suit all budgets, all of which include the full version of the Ross-Tech VAG-COM software.


Package 1
Standard OBD2 Cable with VAG-COM software
For use with all vehicles featuring the DLC connector except 2002 onward model year A4 & A8


Package 2 Pro-2 OBD2 Cable with VAG-COM software
Features LED to indicate connection status.

For use with all vehicles featuring the DLC connector except 2002 onward model year A4 & A8


Package 3
K1-K2 (Twin Com) OBD2 Cable with VAG-COM software

Features twin LEDs to indicate connection status (line one & line two)
For use with all vehicles featuring the DLC connector including 2002 onward model year A4 & A8


Package 4
Pro-2 OBD2 Cable and VAS 5051/2 adapter with VAG-COM software

For use with all vehicles including earlier models featuring the 2x2 connector, but excluding 2002 onward model year A4 & A8


Package 5
K1-K2 (Twin-com) OBD2 Cable and VAS 5051/2 adapter with VAG-COM software

For use with all vehicles including earlier models featuring the 2x2 connector

All cables are German manufactured and come with a 2-year manufacturers warranty.

Please see the VAG-COM products page for pricing details.

Best wishes,

Ram®