( TL19E30A14680800000CAAT10 )

VTEC System Operation
At low engine speed, the rocker arm oil control solenoid is turned off by the ECM/PCM. Oil pressure from the rocker arm oil control valve does not enter the intake rocker shaft. Each intake rocker arm is separated by a return spring and it lifted by each low lift cam lobe.
At high engine speed, the rocker arm oil control solenoid is turned on by the ECM/PCM. Oil pressure from the rocker arm control solenoid enters into the primary intake rocker arm via the intake rocker shaft, and it moves the VTEC switching piston in the rocker arm. This causes the VTEC switching piston to slide into the intake mid rocker arm and the intake secondary rocker arm, locking the rocker arms together. Both intake rocker arms are lifted by the high lift cam lobe.