Circuit Description

Variable Valve Timing (VVT) system controls intake valve timing in response to driving conditions. Engine Control Module (ECM) controls VVT Oil Control Valve (OCV) to ensure correct valve timing. OCV is located in cylinder head, at timing chain side of engine. Oil pressure controlled by VVT OCV is supplied to VVT controller. VVT controller then changes relative position between camshaft and crankshaft. VVT controller is located on front of intake camshaft. DTC P1656 is set if ECM detects an open or short in VVT OCV circuit. Possible causes are:

• VVT OCV circuit is open or shorted.
• Defective VVT OCV.
• Defective ECM.