Transfer Case: Description and Operation

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.

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:

- VTM-4 Control Unit
- VTM-4 Relay
- VTM-4 Lock Switch
- ABS Modulator Control Unit
- PCM
- Right Side Clutch Electromagnetic Coil
- Left Side Clutch Electromagnetic Coil

Fuse 4 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) position.

Fuse 6 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. Fuse 9 located in the Driver's Under-dash Fuse/Relay Box supplies battery voltage to the VTM-4 Control Unit through the VTM-4 Lock Switch when the ignition switch is turned to the ON (II) or START (III) position. The VTM-4 Lock Switch must be closed for the voltage to reach the VTM-4 Control Unit. This signal will indicate the request for VTM-4 lock conditions.

Fuse 60 located in the Auxiliary Fuse Box is hot at all times. When the VTM-4 Relay is closed, battery voltage from Fuse 60 is supplied to the VTM-4 Control Unit.