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Low engine speed

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 the intake secondary rocker arm is lifted by the low lift cam lobe.

Fig 1: VTEC Operation Diagram (Low Engine Speed)

Courtesy of AMERICAN HONDA MOTOR CO., INC.