CMP Actuator System Advance
WARNING: This page is about a different car, the 2003 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.
Oil flowing to the CMP actuator housing from the CMP solenoid advance passage applies pressure to the advance side of the vane wheel in the CMP actuator assembly. See Fig 1 . At the same time the CMP solenoid retard passage is open, allowing oil pressure to decrease on the retard side of the vane wheel. These two simultaneous actions cause the vane wheel to rotate clockwise, advancing camshaft advance timing.