Operation CHARM: Car repair manuals for everyone.

General

Variable Valve Timing System

This engine has a variable valve timing system, which adjusts the opening and closing timings of the valves optimally by continuously changing the phase angle of the camshaft sprocket relative to the camshaft.
- The ECM determines the optimal cam angle relative to the crank angle by making reference to the engine speed, vehicle speed, throttle opening and other relevant parameters.
- Under the control of the ECM, the oil flow control solenoid valve moves its spool to switch the hydraulic passage to/from the advance and retard chambers that are formed in the camshaft sprocket to change continuously the phase angle between the camshaft sprocket and camshaft.