Variable Cylinder Management (VCM) System
WARNING: This page is about a different car, the 2011 Honda Pilot, 2010 Honda Pilot, and 2009 Honda Pilot. However, it is still accessible from the selected car via links, so may be relevant.
The VCM system activates the cylinders based on the driving condition. The system has three modes: 6 cylinder mode (all cylinder operation), 4 cylinder mode (pauses the No. 3 and No. 4 cylinders), and 3 cylinder (pauses the rear bank of cylinders). On paused cylinders, the intake and exhaust valves are kept closed. Since the valves are closed, the frictional losses from the valve spring compression and pumping are reduced because no air is compressed in the cylinder. This reduces engine drag.
NOTE:
Cylinders No. 5 and No. 6 are not controlled by the VCM and operate in all modes.