XC70 L5-2.5L Turbo VIN 59 B5254T2 (2003)
Variable Valve Timing Actuator: Description and Operation
Camshaft Reset Valve
Camshaft Reset Valve (Continuous Variable Valve Timing (CVVT))
The camshaft reset valve controls the oil flow to the CVVT unit (camshaft pulley).
The valve consists of an electro-magnetic valve with a spring-loaded piston. There are slits in the piston which channel the engine lubricating oil to the
CVVT unit by moving the piston in the reset valve. The continuous variable valve timing (CVVT) unit turns the camshaft (the cam timing changes). The
direction in which the camshaft turns depends on the chamber in the CVVT unit which is supplied with oil (pressure). Also see Function.
The system relay supplies the reset valve with voltage. The valve is grounded (control stage) in the engine control module (ECM). When the valve is
grounded using a pulse width modulation (PWM) signal, the oil flow in the valve can be controlled to the different chambers in the continuous variable
valve timing (CVVT) unit at variable rates. This allows the cam timing to be changed precisely and steplessly.
The engine control module (ECM) can diagnose the camshaft reset valve.
The valve is on the cylinder head above the camshaft with camshaft control.