At low engine speed

At low engine speed, the rocker arm oil control solenoid is turned off by the PCM. Oil pressure from the rocker arm oil control valve does not enter the rocker shaft. The primary and secondary rocker arms are separated by a return spring and the intake and the exhaust secondary rocker arms are lifted by the low lift cam lobe.

Fig 1: VTEC System Operation At Low Engine Speed

Courtesy of AMERICAN HONDA MOTOR CO., INC.