Problem with the MONSTER MOTO SHIELD VNH2SP30

Hello,
I have a problem with the MONSTER MOTO SHIELD driver (VNH2SP30):
With one of the VNH2SP30 chips the motor rotates to the left and to the right, but with the other VNH2SP30 chip I can only move the motor in one direction.

i am using "Arduino Uno" and i tried with 6V and 12V, also i tried with several codes.

Thank!!!