SERVO work with SaintSmart but not with ARDUINO

Hi, my name is Eric!

I have a little problem. I have make a delta printer with a SaintSmart and i have a servo for the probe, and the servo work good with M code M340 P0 S...
My problem is i have buy a ARDUINO and program it with the same repetier-frimware 0.91 r7 switch the ramp to the arduino and change nothing, the servo do not respond
to any M code, like if i have no signal. I don't konw if SaintSmart have the same pinout as Arduino? If i put the SaintSmart all work again.

The servo have is own power supply and the signal is connect to ramp D4.

Thanks!

Eric