ch set of two valves are controlled by one rocker arm, which is operated by the camshaft.  Each rocker arm has a slipper follower mounted to the rocker arm with a spring, allowing the slipper follower to move up and down with the high lobe without affecting the rocker arm.  When the engine is operating below 6000-7000 rpm (dependent on year, car, and ECU installed), the low lobe is operating the rocker arm and thus the valves.  When the engine is operating above the lift engagement point, the ECU activates an oil pressure switch which pushes a sliding pin under the slipper follower on each rocker arm.  This in effect, switches to the high lobe causing high lift and longer duration.Toyota has now ceased production of its VVTL-i engines for most markets, because the engine does not meet Euro IV specifications for emissions. As a result, this engine has been discontinued on some Toyota models, including that of the Corolla T-Sport (Europe), Corolla Sportivo (Australia), Celica, Corolla X