Circuit Description

WARNING: This page is about a different car, the 2003 Lexus ES 300. However, it is still accessible from the selected car via links, so may be relevant.

VVT system controls intake camshaft to provide optimal valve timing for every driving condition. This control is performed based on signals of conditions such as intake air volume, throttle position and engine coolant temperature. ECM controls oil control valve (OCV), based on signals output from sensors. VVT controller regulates intake camshaft angle using oil pressure through OCV. As a result, relative positions of camshaft and crankshaft become optimal. Engine torque improves, fuel economy improves and exhaust emissions decrease under overall driving conditions. Also, ECM detects actual valve timing using signals from camshaft position sensor and crankshaft position sensor, and performs feedback control. This is how target valve timing is achieved by ECM. See Figure. If DTC is set, valve timing does not change from current valve timing or current valve timing is fixed after engine is warmed up and engine speed is 400-4000 RPM. Check valve timing, camshaft timing oil control valve assembly, VVT controller assembly, or ECM.