Return the key to the first position, then press and hold the OK button (don't let go) and then turn the key to the second position (for the deluxe version, press the start button), and release it after TEST appears on the display. Then enter the TEST interface, keep pressing the down key to call up the fuel consumption
Pay attention to a few things
1) The screen color will change suddenly during startup, don't be afraid
2) Speedometer, the tachometer will hit the end, that is, turn the head clockwise and come back again, don’t be afraid
3) After tets appear, be sure to release OK, otherwise it will be the same as the normal interface
4) After the engineering mode is completed, press and hold OK to enter the normal mode