E12
Hyundai Power
Under Voltage Protection
Controller shows E12 and the generator will not connect to load.
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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
Weak engine output, AVR (Automatic Voltage Regulator) failure, Loose stator winding connections, Shorted alternator winding
How to Fix / Troubleshooting
Safety first: Turn the generator OFF and lock out the transfer switch. High voltage and rotating parts are hazardous.
- Check engine performance: Start the generator in MANUAL with no load and verify that the engine reaches rated RPM. If it struggles, address fuel/air/ignition issues first.
- Measure output voltage: Using a true-RMS multimeter, measure line-to-line and line-to-neutral voltages at the generator terminals. Compare to the nameplate rating.
- Inspect AVR connections: Locate the Hyundai Power AVR inside the alternator or control box. Check all plug-in connectors and terminal screws for tightness and corrosion.
- Test AVR: If the engine speed is correct but voltage is low or unstable, the AVR may be defective. Replace with the correct Hyundai Power AVR model.
- Alternator inspection: If replacing the AVR does not restore voltage, the alternator windings or diodes may be damaged and require professional testing and repair.
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Repair Difficulty
Professional Required
5/5
Required Part
Automatic Voltage Regulator (AVR)
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