RPM SENSE LOSS
Guardian Engine Speed Signal Loss

Generator cranks and may briefly fire, then shuts down with RPM SENSE LOSS or similar message.

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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

Failed RPM sensor, Loose RPM sensor connector, Damaged flywheel teeth or reluctor ring, Faulty control board RPM input circuit

How to Fix / Troubleshooting

Safety first: Turn the controller to OFF and open the main breaker. Allow moving parts to stop completely.

  • Check sensor wiring: Locate the Guardian RPM sensor near the flywheel. Inspect the connector for corrosion or loose pins. Reseat the connector firmly.
  • Inspect harness: Follow the sensor wiring back to the control panel. Look for cuts, abrasions, or melted insulation. Repair or replace damaged sections.
  • Visual flywheel check: With the engine off and battery disconnected, remove the inspection cover (if accessible) and inspect the flywheel teeth/reluctor ring for missing or heavily damaged sections.
  • Test start: Reconnect the battery, set the controller to AUTO, and perform a manual start. If the fault returns, the RPM sensor or control board is likely defective and should be replaced by a qualified Guardian technician.
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Repair Difficulty

Hard 4/5

Required Part

RPM Sensor
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