Transfer Case Shift Control Module: Notes

The transfer case shift control module performs the following functions:

• Receives input signals
• Processes the signal information
• Develops output signals
• Sends the output signal in order to control the shifting of the transfer case

The transfer case shift control module receives input signals from the following sources:

• The transfer case control switch buttons
• The park/neutral position (PNP) switch on the vehicles with automatic transmissions
• The clutch position switch on the vehicles with manual transmissions
• The powertrain control module (PCM) that supplies the vehicle speed signals
• The encoder motor that provides actual mode and range information signals
• The data link connector pin D3 that actuates diagnostic enable
• Power for the module and motor supplies
• The ground used for return lines at the module

The transfer case shift control module outputs signals to the following components:

• Transfer case encoder motor to initiate mode and range shifts
• Transfer case control switch indicator lamps to provide transfer case status information
• Diagnostic DTCs which are outputted via the shift control switch indicator lamps
• Encoder power

In order to ensure the electronic shift system is operating properly, the transfer case shift control module continually performs diagnostics checks on itself and other parts of the electronic shift system when the ignition switch is in the run position.

The following are different types of system checks that the transfer case shift control module continually performs.