CMP Actuator Assembly

The CMP actuator assembly has an outer housing that is driven by the engine timing chain. Inside the assembly is a wheel with fixed vanes that is attached to the intake camshaft. The CMP actuator assembly also contains a lock pin that prevents movement between the outer housing and the wheel vane assembly. See Fig 1 . The lock pin is released by oil pressure before any movement in the CMP actuator assembly takes place.

Fig 1: Identifying CMP Actuator Components

Courtesy of GENERAL MOTORS CORP.