Circuit Description

NOTE: Variable Valve Timing (VVT) sensor may also be referred to as camshaft position sensor.

NOTE: Bank No. 1 refers to bank which includes cylinder No. 1. Bank No. 2 refers to bank without cylinder No. 1.

The Variable Valve Timing (VVT) system controls intake valve timing in response to driving conditions. Engine Control Module (ECM) controls Oil Control Valve (OCV) to ensure correct valve timing. A OCV is located in each cylinder head at flywheel side of engine. Oil pressure controlled by the OCV is supplied to the VVT controller. VVT controller then changes relative position between camshaft and crankshaft. VVT controller is located on the front of each intake camshaft. DTC P1656 or P1663 is set if ECM detects an open or short in OCV circuit. DTC P1656 is for bank No. 1 (right cylinder head) OCV circuit. DTC P1663 is for bank No. 2 (left cylinder head) OCV circuit. Possible causes are:

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