Circuit Description

The Variable Valve Timing (VVT) system controls the intake valve timing in response to driving conditions. ECM uses input from Crankshaft Position (CKP) sensor and Variable Valve Timing (VVT) sensor to control the Oil Control Valve (OCV). OCV varies oil pressure between 2 circuits, changing intake camshaft position as much as 50 degrees of crankshaft angle.

DTCs P1656 and P1663 are set when ECM detects an open or short in OCV circuit. Possible causes are:

• Open or short in Oil Control Valve (OCV) circuit.
• Oil control valve.
• ECM.