Service function guideVariable Valve Timing Service

This guide covers the complete inspection and service of variable valve timing (VVT) systems, focusing on cam phasers and oil control valves across common gasoline engines. It is written for working mechanics and experienced DIYers who already understand four-stroke engine operation and have basic diagnostic scan tool skills. You will learn how the VVT system hydraulically and electronically adjusts camshaft timing, how to recognize the symptoms of a failed phaser or clogged solenoid, and how to safely remove, clean, test, and replace these components. After finishing, you will be able to perform a systematic VVT service, verify the repair with live data and a road test, and avoid the costly mistakes that lead to repeat failures.