Camshaft Actuator System Description: Notes

The camshaft (CMP) actuator system enables the engine control module (ECM) to change camshaft timing of all camshafts while the engine is running. The CMP actuator assembly varies the camshaft position in response to directional changes in oil pressure. The CMP actuator solenoid valve controls the oil pressure that is applied to advance or retard a camshaft. Modifying camshaft timing under changing engine demand provides better balance between the following performance concerns:

• Engine power output
• Fuel economy
• Lower tailpipe emissions

The CMP actuator solenoid valve is controlled by the ECM. The crankshaft position (CKP) sensor and the CMP sensors are used to monitor changes in camshaft positions. The ECM uses the following information in order to calculate the desired camshaft positions:

• The barometric pressure (BARO)
• The camshaft position (CMP) sensors
• The crankshaft position (CKP) sensor
• The engine load
• The engine speed
• The manifold absolute pressure (MAP) sensor
• The throttle position (TP) sensors