VAGCOM is a hardware and software setup to interface a computer to the TReg (and other VW/Audi car) diagnostic port. It can be used to check fault codes, and activate/control several features. For example, using a VAGCOM setup and the appropriate codes, you can disable the obnoxious seatbelt warning chime. Similarly, you can set up your TReg so you can turn off the Daytime Running lights using you MFI controls. (Unlike many cars, the DRL's are on whenever the car is on. Most cars, and othe VW's, only have the DRL's on when the car is in drive, or the parking brake is off. One may want to disable this feature so that when you are sitting in the car waiting for someone at a parking lot (for example) you can leave the engine running, but have the headlights off.)michelle said:what is a vagcom?