Circuit Description

The variable valve timing (VVT) system controls intake valve timing to proper timing in response to driving condition. ECM controls oil control valve (OCV) to make intake valve timing properly, and, oil pressure controlled by OCV is supplied to VVT controller, and then, VVT controller changes relative position between camshaft and crankshaft. Detecting condition of DTC is when following conditions continue after engine is warmed up and engine speed is at 400-4000 RPM:

• Valve timing does not change from of current valve timing.
• Current valve timing is fixed.