Vacuum display shows E11; unit may not start or may run erratically; often after a drop or impact.

Safety first: Remove the battery pack before opening any part of the vacuum body.

• Power reset: With the battery removed, hold the power button for 15–20 seconds to discharge residual power. Reinstall the battery and test again.
• Check for physical damage: Inspect the main body for cracks or signs of impact that may have dislodged internal components.
• Advanced inspection: If you are experienced with small appliance repair, open the main body to access the motor and control board. Verify that the small sensor connector from the motor to the PCB is firmly seated.
• Replace sensor/motor assembly: On many Tristar cordless vacuums, the Hall sensor is integrated into the motor assembly. If the error persists and wiring is intact, replacing the entire motor assembly is typically required.