E09
Audi Surge Protection / Internal Self-Test Failure

Audi wallbox displays E09 and charging is disabled; often appears after a lightning storm or grid disturbance.

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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

Triggered internal surge protection device (SPD), Damaged MOVs or surge components on power board, Overvoltage event from grid, Faulty self-test circuitry on main board

How to Fix / Troubleshooting

Safety first: Overvoltage damage can compromise insulation and safety. If you suspect a lightning strike, have the entire system inspected.

  • Power-cycle the unit: Turn off the dedicated breaker for 5–10 minutes, then restore power. Some surge protection circuits will reset if the event was minor.
  • Inspect for visible damage: With power off and cover removed by a professional, inspect the power board for burnt components, cracked MOVs (metal-oxide varistors), or charred PCB areas.
  • Check external surge protection: Ensure that any upstream surge protective devices in the distribution board are intact and correctly rated. Replace tripped or failed SPDs.
  • Replace damaged boards: If E09 persists and visual inspection shows damage, replace the power board or main control board assembly as specified by Audi. After replacement, perform full functional and safety tests.

Consider adding or upgrading external surge protection if your area is prone to lightning or grid disturbances.

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Repair Difficulty

Professional Required 5/5

Required Part

Surge Protection Components on Power Board
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