Hi I am using a Teensy 4.0 to run my robot (motors, LIDAR and Limit sensors). It works fine when I am connected to the PC (usb cord) but when I only use external power (not connected via usb from PC).

I removed all reference to the Serial like Serial.begin and Serial.print but it stop at the Delay() command. weird.

Can anyone point me in the right direction

Thank you in advance