Gone are the days of carburetors and point ignition systems. Technology has made the automobile faster, safer, cleaner and more reliable, but with the added complexity comes new obstacles that hand tools can't remedy. Where once a toolbox and elbow grease were a broken car's salvation, now microprocessors and intricate diagnostic tools are the means to a healthy ride.
In recent years, these shifting tides made it virtually impossible for consumers to diagnose or fix problems without expensive dealer-specific computers. While an enthusiast might be a proficient mechanic, a simple check engine light (CEL) would necessitate a $100 trip to the dealer for diagnosis only because the consumer didn't have access to the right tools.
The only way to read a VW or Audi's computer used to be with the dealer-only VAG-1552/1551 diagnostic tool. Once connected, this electronic wonder took the guesswork out of troubleshooting, finding fault codes and problems through interrogating on-board microprocessors and modules. But now, thanks to an ingenious enthusiast, the power of dealer diagnostics is available to the public.
History Lesson
Back in '97, Uwe Ross was a frustrated VW enthusiast with a deep knowledge of programming. After finding it impossible to work on his GTI without the necessary computer, he did like any gear-head programmer would do and began work on reverse-engineering a VAG-1552. After three years he cracked the code and created a Windows PC-based equivalent called the Ross-Tech VAG-COM, placing the electronic toolbox in the consumer's hands.
While VAG-COM won't replace a repair manual, nor will it tune the ECU, it gives the user access to the car's processor, while also helping monitor and locate broken or ill-performing parts and procedures. In other words, if used with the proper repair manual, it should make it possible to work on your VW or Audi again.
What does this mean to the average enthusiast? The gurus at Ross-Tech explained that one of the many tricks the VAG-COM can perform is check and clear CEL codes. This allows the user to monitor random or recurring problems and decipher if the part triggering the fault code needs repair or replacement.
Often a random fault code will register and, once cleared, will never return, but sometimes the fault resurfaces. The Ross-Tech technicians explained that even though a code might be intermittent, if it continues to register it usually means the suspect part is malfunctioning.
Prior to tools like the VAG-COM, simply tracking down an intermittent problem was more difficult than fixing it; with a VAG-COM the investigation is essentially done for you.
To the tech aficionado, the VAG-COM can be more than a diagnostic code retriever, since it offers more features than the factory VAG-1552 units. Options include live datalogging, freeze-frame capability, basic settings, resetting service intervals, output tests and readiness settings.
In addition to these invaluable features, you can alter the ride height on factory air suspension, add window up and down features on your key fob and even calculate 0-60mph, quarter-mile and other acceleration times where the applicable factory equipment is fitted.
VAG-COM can even be used to log a car's parameters while hot lapping, allowing you to focus on specific incidents where codes were thrown. It can also be used to reset things like radio presets, throttle body adaptation and auto-leveling headlights.