Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Circuit Description
The Variable Valve Timing (VVT) system controls intake valve timing in response to driving conditions. Electronic Control Module (ECM) controls Oil Control Valve (OCV) to ensure correct valve timing. An OCV is located in each cylinder head at flywheel end of engine. Oil pressure controlled by OCV is supplied to VVT controller. VVT controller then changes relative position between camshaft and crankshaft. VVT controller is located on 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 (left cylinder head) OCV circuit. DTC P1663 is for bank No. 2 (right cylinder head) OCV circuit. Possible causes are:
- Open or short in OCV circuit.
- Faulty OCV.
- Faulty ECM.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.