E07
Hyundai Power Products Under Voltage / AVR Regulation Fault

Generator runs but controller shows E07 and output voltage is low or unstable

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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

Faulty Automatic Voltage Regulator (AVR), Loose stator or rotor connections, Worn brushes or slip rings (if brush-type alternator), Weak excitation circuit

How to Fix / Troubleshooting

Safety first: Turn OFF the generator, open the main breaker, and disconnect battery negative. Wait for all rotating parts to stop.

  • Inspect alternator connections: Remove the alternator terminal box cover on the Hyundai generator. Check all stator output terminals and excitation wiring for loose screws, discoloration, or burnt insulation. Tighten and clean as needed.
  • Check AVR connections: Locate the Hyundai AVR module inside the alternator or control compartment. Ensure all plug-in connectors are fully seated and free of corrosion.
  • Visual AVR inspection: Look for burnt components or a burnt smell on the AVR. If present, the AVR should be replaced.
  • Brush/slip ring check (if applicable): On brush-type Hyundai alternators, inspect brushes for wear and ensure they move freely in their holders. Clean slip rings with fine emery cloth.
  • Replace AVR: If voltage remains low or E07 persists, replace the AVR with the exact Hyundai-specified model. After replacement, adjust voltage according to the service manual using the AVR trim pot if provided.
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Repair Difficulty

Hard 4/5

Required Part

Automatic Voltage Regulator (AVR)
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