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

Donald