E12 appears and unit beeps; brush motor starts then stops within a few seconds

Safety first: Unplug the unit before accessing the brush motor or control board.

• 1. Access brush motor assembly
  • Remove the floor nozzle cover and any additional screws to expose the brush motor.
  • Locate the tachometer sensor (often a small Hall or optical sensor near the motor shaft).
• 2. Inspect tach wiring
  • Check the small-gauge wires from the motor to the main harness for breaks or disconnection.
  • Reseat connectors and repair damaged wires.
• 3. Clean tach wheel / magnet
  • If an optical sensor is used, clean the slotted wheel and sensor window with a soft brush.
  • Ensure the wheel is not loose on the shaft.
• 4. Test sensor
  • Using a multimeter or oscilloscope (for professionals), verify that the tach sensor outputs pulses when the motor is spun.
  • If no signal is present, replace the brush motor assembly or tach sensor, depending on design.
• 5. Control PCB check
  • If the sensor is known good but E12 persists, the speed feedback circuit on the PCB may be defective and the board should be replaced.