Theory Of Operation

For Multi Displacement Solenoid (MDS) to activate, power is supplied to each MDS when the engine is making a transition from 8 cylinder mode to 4 cylinder mode. By actuating the solenoid, oil pressure is raised to the pair of lifters that coincide with each particular solenoid. The oil pressure pushes in the locking pins that allows the lifter to collapse, decoupling the valves and camshaft.

In reactivation mode, the MDS is de-energized and oil pressure is lowered to each particular solenoid and the locking pins are released which allows full lift of the lifters.