The CWT system enhances fuel consumption and decreases the amount of nitrogen oxide (NOx) released into the atmosphere through continuously changing intake camshaft phase and, as a result, valve overlap possibilities. In response to shifting operating conditions, the CWT system varies intake valve timing incessantly. The Camshaft Position (CMP) sensor, oil temperature sensor, other sensors, Powertrain Control Module (PCM), oil control valve and CWT assembly itself located on the end of the exhaust camshaft make up the CWT system. The PCM processes this information by taking inputs from several sources such as: Oil Pressure/Temperature; Engines camshafts & crankshafts position; Vehicle speed etc. It then uses this processed information to send signals to open or close an OCV command may be sent by itself in response to some input. Home mechanics are not trained to diagnose faults in the control of VCT systems. However there are components that you can replace at home. Component replacement procedure for CWT assembly is provided in 2A below: The procedure for replacing OCV and its filter is contained herein below: Elsewhere in this guide are procedures for replacing various other sensors. It is situated on top left corner of cylinder head next to intake manifold . Take off engine cover. Unplug electrical connector from OCV.Remove bolt retaining OCV and extract it.Then install what you have removed vice versa.Oil control valves filter is underneath oil control valve threaded into left side of cylinder head.Take off engine cover.Unscrew OCV filter.Remove old gasket of old oil control valves installation is similar with removal.Ensure use of OCV filter gasket with secure tightening.Be sure that your engine does cool before doing it.This sensor sits below oil control valve at front engine.Put rags under sensor where any spillage may occur.Disconnect wiring from it then remove.Use wrench only on hex flats of sensor so as not spoil its shape.Fit it back the way you remove.