Vibe FWD L4-1.8L VIN 8 (2004)
Variable Valve Timing Actuator: Description and Operation
Camshaft Actuator System Description
1 - Camshaft Position (CMP) Sensor
2 - Engine Coolant Temperature (ECT) Sensor
3 - Camshaft Position (CMP) Actuator Solenoid Valve
4 - Crankshaft Position (CKP) Sensor
5 - CMP Actuator Assembly
6 - Intake Camshaft
7 - Exhaust Camshaft
The camshaft position (CMP) actuator system enables the powertrain control module (PCM) to change camshaft timing while the engine is running. The
CMP actuator assembly (5) varies 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 the 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 (3) is controlled by the PCM. The crankshaft position (CKP) sensor (4) and the CMP sensor (1) are used to monitor
changes in camshaft position. The PCM 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 (TP) sensor
*
The vehicle speed sensor (VSS)
Camshaft Position (CMP) Actuator Assembly
1 - Lock Pin
