F4
Vax Internal Sensor / Orientation Fault

Cordless Vax vacuum shows “F4” and will not start; may occur 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

Dislodged tilt/orientation sensor on PCB, Internal connector loosened by impact, Damaged main control PCB from shock

How to Fix / Troubleshooting

Safety first: Remove the battery before handling the vacuum.

  • 1. Power reset: Remove the battery for 5–10 minutes. Press and hold the trigger for 10 seconds (battery removed) to discharge the electronics. Refit the battery and test.
  • 2. Check for physical damage: Inspect the housing for cracks, gaps, or loose panels that may indicate internal damage.

If F4 persists and the unit has been dropped, internal sensors or the PCB are likely damaged. This requires professional disassembly and PCB replacement.

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Repair Difficulty

Professional Required 5/5

Required Part

Main Control PCB
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