Using a is a common but high-risk method for accessing Toyota's proprietary diagnostic software without paying the official subscription fees, which can cost $1,545 for hardware and annual access or $65 for a two-day license.
Also, think about technical details. How does the keygen work? Does the story need to explain that? Maybe not in depth, but enough to make it believable. The software could have anti-piracy measures that cause problems when the keygen is used.
In most enthusiast circles, the activation process for v15 generally follows these steps: Maintech Installation : Installing the core Techstream_Setup_V15.xx.xxx.exe Driver Setup