4WD Control System Description
The 4WD control system is divided into “Air Locking Hub Control System” and “Transfer Control System”.
The air locking hub control system is described in this section
For transfer control system description, refer to 4WD Control System Description .
Air Locking Hub Control System
The air locking hub control system consists of a 4WD switch, a 4WD control module, a vacuum switch, a vacuum tank (for M13A engine mode), a vacuum pump (for K9K engine model), two vacuum switching valves (VSV1 and VSV2) and air locking hub assemblies.
The 4WD control module controls locking or unlocking of the air locking hub according to the signal from the 4WD switch installed in the transfer.
For M13A engine, vacuum generated in the intake manifold passes through the check valve and stored in the vacuum tank.
For K9K engine, vacuum generated by vacuum pump passes through the vacuum control valve which regulate vacuum pressure.
According to signals from the 4WD switch, the 4WD control module activates VSV1 (for unlocking) or VSV2 (for locking) to apply vacuum to wheel hub from the vacuum tank or pump so that the front axle and the wheel hub are disengaged or engaged.