Problem:

The Kohler Diagnostic System Software is installed, but I don't know what Serial Number was used to install it.

Solution:

The Software Serial Number was included in the original Kohler Diagnostic System Kit you received. This is the kit that came with a CD, Manual and the Vehicle Interface Cable in one box. Depending on when you received this kit, the Serial Number was either on a "Serial Number Card" or on a label attached to the CD Sleeve.