Transfer Case: Description and Operation

VTM-4 System (Variable Torque Management 4-Wheel Drive)

How the Circuit Works
The Variable Torque Management 4WD (VTM-4) System distributes driving torque between the front and rear wheels when accelerating. The VTM-4 system also distributes driving torque when any of the wheels lose traction and are slipping. The VTM-4 control unit controls the current flowing through the electromagnetic coils to engage and disengage the right and left clutches in the rear differential.

When the vehicle is stopped and the transmission is in the R, 2, or 1 positions, the system will fully lock the rear differential clutches when the VTM-4 Lock Switch is pressed.

The major components that make the VTM-4 system work are:
- Differential Oil Temperature Sensor
- VTM-4 Control Unit
- VTM-4 Relay
- VTM-4 Lock Switch
- VSA Modulator Control Unit
- PCM
- Right Side Clutch Electromagnetic Coil
- Left Side Clutch Electromagnetic Coil

Fuse 9 located in the Driver's Under-dash Fuse/Relay Box supplies battery voltage to the VTM-4 Control Unit when the ignition switch is turned to the ON (II) or START (III) position.

Voltage from Fuse 9 will also be supplied to the VTM-4 Control Unit when the VTM-4 Lock Switch is pressed and manually closed. This voltage signal will indicate the request for VTM-4 lock conditions.

Fuse 1 ('03-'04) or fuse 4 ('05-'06) located in the Under-hood Sub-fuse Box supplies battery voltage to the VTM-4 Control Unit when the VTM-4 relay is closed.