Good morning, you must change the pushbuttons for a similar one, now when several are removed to test if one is crossed, it is when the electronic card does not turn on and the blocking of the ignition is suspected. If Start is not activated even if the button is changed, you should check the copper tracks of the same button are not cut or raised, follow all the way of both tracks until you reach the microcontroller, you must use a good magnifying glass, enough light and a multimeter to mediate continuity. When opening the card and removing the plastics, care must be taken as it may tear a track on the printed circuit.