Transfer Case Control Module Description

1. The Transfer Case Control Module (TCCM) 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

2. The TCCM receives input signals from the following sources:
^ The transfer case shift select buttons
^ The NSBU switch on the vehicles with automatic transmissions
^ The clutch position switch on the vehicles with manual transmissions
^ The vehicle sped sensor calibrator module
^ The encoder/motor range and the mode feedback signals
^ The diagnostic enable
^ The front axle mechanical status signal

3. In order to ensure the electronic shift system is operating properly, the transfer case control module (TCCM) 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 TCCM continually performs.

- RAM/ROM Check
- Data Memory Retention Check
- Encoder Signal Check
- Encoder Switch Monitor Check
- Motor and Relay Voltage Checks