CMP Actuator System Operation
WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
The camshaft position (CMP) actuator system is controlled by the engine control module (ECM). The ECM sends a pulse width modulated 12-volt signal to a CMP actuator solenoid to control the amount of pressurized engine oil, into the CMP actuator. To regulate the pressurized engine oil into the CMP actuator, the solenoid uses electromagnetic force on the solenoid pintle to pulse the oil control spool valve. The pressurized engine oil is sent to unseat the locking pin, and to the vane and rotor assembly of the CMP actuator, to either retard or advance the valve timing. The ECM will control the amount of ON time applied to the solenoid.