E04
Webasto Internal Overtemperature Protection Trip

Charging stops; charger shows E04 indicating overtemperature; unit may resume after cooling.

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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

Blocked ventilation openings on Webasto housing, High ambient temperature above specification, Failing internal cooling fan (if equipped), Loose or overheated terminal connections

How to Fix / Troubleshooting

Safety first: Turn off power at the breaker before touching the charger housing for inspection.

  • Check ambient conditions: Ensure the charger is not installed in direct sun or in a confined, unventilated space. Ambient temperature should be within Webasto’s specified range.
  • Inspect vents: Remove dust, spider webs, or debris from ventilation slots using a soft brush or vacuum. Do not spray water or cleaners into the unit.
  • Feel for hot spots: After a charge session, carefully feel the front and sides of the housing. Excessive localized heat may indicate loose internal connections and requires a technician.
  • Reduce charging current: If your Webasto model allows current setting (via DIP switches or app), temporarily lower the maximum current and see if E04 stops occurring.
  • If overheat persists: An internal temperature sensor or fan may be defective. Contact a qualified Webasto service partner for internal inspection and part replacement.
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Repair Difficulty

Hard 4/5

Required Part

Webasto Internal Temperature Sensor / Cooling Fan
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