Circuit/System Description

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

• Engine power output
• Fuel economy
• Lower exhaust emissions

The camshaft position actuator solenoid valve - Intake and camshaft position actuator solenoid valve - exhaust is controlled by the ECM. The crankshaft position sensor and the camshaft position sensor - intake and camshaft position sensor - exhaust are used to monitor changes in camshaft position. The ECM uses information from the following sensors in order to calculate the desired camshaft position:

• The engine coolant temperature (ECT) sensor
• The mass air flow (MAF) sensor
• The throttle position sensor
• The vehicle speed sensor (VSS)