Hi again.
I think problem is solved,finnaly!Last time i went to the costumer the machine was failling more constantly,so i put display in TOD mode3 to check the current codes,and code 31-1 apears each time the reach truck traction was shut down.
Replace the accel. pot and machine is working good until today.Simple resolution when we get there,but wouldnt be possible without your help,thanks to you all.
Best regards