Transfer Case Shift Control Module:

The transfer case shift control module uses the VIN information for calculations that are required for the different calibrations, based on axle ratio, transmission, tire size, and engine. The system does not know which calibration to use without this information. This information is provided to the transfer case shift control module via Class 2 data bus from the powertrain control module (PCM). The transfer case shift control module monitors front and rear propshaft speed, as well as controlling the operation of the transfer case encoder motor assembly and the engaging and disengaging of the front axle.