The VC-15W alternator tester is a handheld, very useful and easy to use device, used by car garages, diagnostic stations, authorised service stations and rebuilders.
The VC-15W allows you to diagnose an alternator that is communicating with the ECU of the car, even when it's still mounted or to be used in combination with
all conventional test benches. These "modern" alternators can't be diagnosed by using a regular voltage meter.
The ECU communication systems are found on cars starting from 2002 and up, and are known as LIN (Local Interconnect Network) and BSS(Bit Synchronous Single-wire) systems, and even earlier as Ford or GM's PWM(Pulse Width Modulation) systems.