What U400 Means on a Bosch Induction Cooktop

Bosch's current US standalone induction-cooktop support defines U400 as supply voltage outside the normal operating range. The code confirms what the cooktop is reporting; it does not identify whether the utility/branch voltage, installation connection, a termination, or internal sensing is responsible.

U400 Is Not an E9011 Parts Verdict

Bosch's slide-in range surface lists E9011 for improper appliance connection and also lists U400 separately. A standalone cooktop U400 page must not claim that E9011 is the same code, nor may U400 be used to name a failed control board. Exact appliance type and E-Nr remain controlling.

Safe Checks That Change the Diagnosis

  • Photograph U400: Capture the entire panel and affected zone state.
  • Record the model: Photograph the full E-Nr, including suffix, plus FD/serial.
  • Note the event: New installation, move, electrical work, outage, or ordinary use.
  • Check visible context only: Record a breaker trip, whole-unit reset, heat, odor, or discoloration without opening anything.

What Not to Do

  • Do not remove the cooktop or terminal cover.
  • Do not test live voltage, move conductors, alter jumpers, or change breaker size.
  • Do not blame the utility, installer, or control module before measurements.
  • Do not translate the code using a different Bosch appliance family's list.

Stop Using the Cooktop When

Leave power off if U400 returns after the model-documented action, the breaker trips, the cabinet or connection area heats abnormally, or there is smoke, arcing, or electrical odor.

What a Technician Must Confirm

A qualified technician compares measured branch voltage and connection configuration with the complete E-Nr nameplate and installation diagram, inspects terminations de-energized, and observes voltage under controlled load. If the external supply and connection are correct, internal voltage sensing and power electronics become the next service boundary.

What to Record Before Service

  • Identity: Complete E-Nr, FD/serial, and U400 photo.
  • History: Installation date and recent outage, move, or electrical work.
  • Scope: One zone indication or whole-cooktop behavior.
  • Safety signs: Trip, heat, odor, arcing, or discoloration.

FAQ

Who should I contact for U400?

Bosch's current US action is to contact your electrical utility provider or Bosch Customer Support. Keep the U400 photo and complete E-Nr available; do not open the cooktop or choose a part from the code.