E7
Bomann Internal Communication Error / Sensor Bus Fault

LED display shows E7 and vacuum will not start, often after a drop or impact

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Loose connector between battery pack and main PCB, Damaged internal wiring harness from handle to motor, Faulty sensor (e.g., temperature or current sensor) on main PCB, Cracked main PCB due to impact

How to Fix / Troubleshooting

Safety first: Remove the battery pack before opening any covers. Do not operate the vacuum if you see exposed or damaged wiring.

  • Step 1 – Reseat battery: Remove the battery and reinstall it firmly until it clicks. Check that there is no play in the connection.
  • Step 2 – Visual inspection: Look for obvious cracks in the housing or signs of impact. If the vacuum was dropped, internal components may have shifted.
  • Step 3 – Check external connectors: Inspect the contacts between the main body and any detachable wand or motorized head. Clean them with a dry cloth.
  • Step 4 – Power reset: Leave the battery out for 5 minutes, then reinstall and try again.
  • Step 5 – Internal inspection (only if allowed by manual): If your Bomann model allows user access to the motor compartment, carefully remove the screws and open the housing. Check that all plug-in connectors on the main PCB are fully seated. Do not touch bare solder joints or components.

If E7 remains after reseating connectors and performing a reset, the main PCB or internal sensor network is likely damaged. Professional diagnosis and PCB replacement are recommended.

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Repair Difficulty

Professional Required 5/5

Required Part

Internal Wiring Harness
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