E4
Hilti
Electronics / Control PCB Failure
Vacuum does not start; LEDs indicate fault E4; battery works fine on other Hilti tools
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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
Damaged main control PCB, Burnt MOSFET or power transistor, Internal short due to dust ingress, Corroded PCB connectors
How to Fix / Troubleshooting
Safety first: Remove the battery pack. Do not attempt to bypass electronic safety circuits.
- Visual inspection: Check the exterior for impact damage or signs of water ingress. If the vacuum has been exposed to rain or slurry, internal electronics may be compromised.
- Check user controls: Verify that the on/off switch and any mode selector are not physically broken or jammed. A broken switch lever can mimic PCB failure.
- Battery interface check: Inspect the battery terminals on the vacuum for looseness or broken solder joints (if visible through vents). Excessive movement can damage the PCB.
- Do not open sealed electronics: The control PCB is typically potted or protected. Opening the housing without proper ESD precautions can cause further damage and void warranty.
- Service recommendation: If the battery is known-good and the tool still shows E4, the main control PCB must be tested and replaced by an authorized Hilti service center.
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Repair Difficulty
Professional Required
5/5
Required Part
Main Control PCB
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