Camshaft Position (CMP) Actuator System
WARNING: This page is about a different variant/trim than selected.
The camshaft position actuator system enables the engine control module (ECM) to change camshaft timing while the engine is running. Modifying camshaft timing under changing engine demand provides better balance between the following performance concerns:
Camshaft Position Actuator System
| Driving Condition | Change in Camshaft Position | Objective | Result |
|---|---|---|---|
| Idle | No Change | Minimize Valve Overlap | Stabilize Idle Speed |
| Light Engine Load | Retard Valve Timing | Decrease Valve Overlap | Stable Engine Output |
| Medium Engine Load | Advance Valve Timing | Increase Valve Overlap | Better Fuel Economy with Lower Emissions |
| Low to Medium RPM with Heavy Load | Advance Valve Timing | Advance Intake Valve Closing | Improve Low to Mid-range Torque |
| High RPM with Heavy Load | Retard Valve Timing | Retard Intake Valve Closing | Improve Engine Output |
The CMP actuator system is controlled by the ECM. A camshaft position actuator solenoid oil control valve directs engine oil pressure supplied to the CMP actuator to advance or retard the camshaft. The crankshaft position (CKP) sensor and camshaft position (CMP) sensors are used to monitor changes in camshaft positions. The ECM uses the following information in order to calculate the desired camshaft advance or retard from base timing:
- The barometric pressure (BARO)
- The camshaft position (CMP) sensors
- The crankshaft position (CKP) sensor
- The engine coolant temperature (ECT) sensor
- The engine load
- The engine speed
- The manifold absolute pressure (MAP) sensor
- The throttle position sensor
- The vehicle speed sensor (VSS)