ESC can‘t detect the throttle signal in pixhawk 2.4.6

Hi,

I am trying to make a boat using skid steering.I use a pixhawk 2.4.8 and ardurover 4.0 at first,and the esc can detect normally the throttle signal . But when I replace pixhawk 2.4.8 with pixhawk 2.4.6,the esc’s leds wil keep flashing .It means esc can‘t detect the throttle middle signal according to the mannual.

I have two pixhawk 2.4.8 and pixhawk 2.4.6. It use the same param setting and firmware.After I found that only pixhawk 2.4.8 can be detect normally by ESC .I use unbranded diy ESC,and I can provide more information about it .

And Is there a big difference between pixhawk 2.4.8 and pixhawk 2.4.6?

Has anyone encountered this problem? Looking forward to your reply.