if the LED display is showing 2 dashes and a blinking dot in the corner that means it is in powered on mode with no faults.
Even if there is a fault it may not always show up when powered on, you will have to select a drive or lift mode and move the joystick to get it to display a fault if one exists. There should be an information placard on the side near the LED display on the ground control area showing you what fault codes mean.
Ironically nowhere in any of the manuals does it tell you what the normal mode display looks like but it is 2 dashes and a blinking dot.