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 camshaft timing changes). The direction in which the camshaft turns depends on the chamber in the CVVT unit which is supplied with oil (pressure). See also: CAMSHAFT CONTROL (CVVT)
An oil filter is mounted at the intake channel for the valves to prevent oil contaminants from affecting the function of the reset valves.
The system relay supplies the reset valve with voltage via a fuse. The valve is grounded (control stage) internally 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 regulated to the different chambers in the continuous variable valve timing (CVVT) unit at variable rates. This allows the angle position to be changed precisely and steplessly.
It is important not to mix up the pipes for the valves when removing/installing the reset valve camshaft.
The engine control module (ECM) can diagnose the camshaft reset valve.
The valves are on the cylinder head above the camshafts. There are four reset valves, two for the inlet camshaft and two for the exhaust camshaft.