E2
MUSTART Input Voltage Out of Range / Overvoltage or Undervoltage Protection

Charger shows “E2” and refuses to start charging; sometimes appears immediately after plugging into the wall or after a power fluctuation.

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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

Incorrect supply voltage (e.g., 120 V on a 240 V MUSTART unit), loose or overheated plug on NEMA outlet, undersized or long extension cord causing voltage drop, wiring issue in supply circuit or receptacle

How to Fix / Troubleshooting

Safety warning: High voltage is present. Do not remove outlet covers or open the charger. If you are not comfortable working around electrical panels, contact a licensed electrician.

  • Verify outlet type: Confirm that the MUSTART charger model matches the outlet (e.g., NEMA 14-50, 6-50, 10-30). Using adapters or the wrong outlet type can cause E2.
  • Avoid extension cords: Plug the charger directly into the dedicated outlet. MUSTART chargers are designed to be used without extension cords.
  • Check for heat and looseness: After turning off the breaker, gently check if the outlet is loose in the wall or shows signs of melting or discoloration. If so, stop using it and call an electrician.
  • Measure voltage (qualified person only): Have an electrician measure the line-to-line and line-to-ground voltage at the receptacle. If it is outside the charger’s rated range (typically around 200–250 V for 240 V units), the supply must be corrected.
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Repair Difficulty

Medium 3/5
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