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View Full Version : Why would I want a VAG-COM and WTF is it anyway?



Ram
January 8th, 2003, 15:46
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®

Drystone
January 8th, 2003, 17:10
Nice description Ram .

Had an idea what it was but now all is clear.

Cheers,

Christian

Doug_RS2
January 8th, 2003, 20:09
I have a 95 S2 and I want VAG-COM. Am I right in thinking I need a OBD11 converter, the the adapter cable for older cars and the license(and a laptop and cable). How much is this in the UK?

Thanks

Joshie
January 9th, 2003, 11:39
[ QUOTE ]
I have a 95 S2 and I want VAG-COM. Am I right in thinking I need a OBD11 converter, the the adapter cable for older cars and the license(and a laptop and cable). How much is this in the UK?Thanks

[/ QUOTE ]

Perhaps this is why I cannot get VAG cCOM to work on my wifes 1998 A3 - because I need an adapted cable which I assume fits between the OBDII cable and the serial port.

Ram - can you shed any light?

toasty
January 9th, 2003, 11:52
Works with my S4 Joshie and that's a 1998 (so is yours isn't it?)

The only problem I had was getting the damn thing to fit in the hole. (bit of work with some small files and I was ok though.)

Perhaps yours just isn't going in far enough


In fact I had heard something..... (no I'll leave it!)

Joshie
January 9th, 2003, 11:55
Well it works with my S4 but not on my wifes A3. Because I'm a cheapskate VAG-COM cant help me especially since I bought the cable from sk.

There will be a solution somewhere

Ram
January 9th, 2003, 13:11
If you want to use VAG-COM on your S2, you'll need the following:

<ul type="square"> VAS 5051/2 adaptor
VAG Com cable compatible with the VAS 5051/2 adaptor
VAG-COM software
Notebook PC or equivalent [/list]
If you've already bought a VAG-COM cable that isn;t compatible with the VAS 5051/2 adaptor, you'll need to replace it!


VAS-5051/2 adapter pictured

Hope this helps!

Ram®