DIAGNOSIS The LCD display is on a separate circuit from the motor. A blank screen with functional suction indicates a software freeze or a poor connection to the piezo sensor.
FIX Perform a hard reset. Turn the vacuum on. Hold the power trigger down. While holding it, remove the battery. Continue holding the trigger for 15 seconds. Release. Reinstall the battery and turn on.
IF THAT DIDN'T WORK Check the filter cover sensor. Open the filter cover and close it firmly until it clicks. The display is disabled if the system thinks the filter door is open.
HEADS UP The particle count graphics require sufficient airflow to activate the sensor. Running the vacuum with a clogged filter or full bin will also result in a dormant display.