ERROR CODE EXPLAINED
Thermador Induction Cooktop
Thermador Induction Cooktop U400 Error Code
What it means
Thermador says U400 indicates an electrical supply-voltage or connection problem.
Try this first
- Have the supply voltage and electrical connection checked by a qualified professional.
Can I keep using it?⚠ Thermador says U400 indicates an electrical supply-voltage or connection problem.
Repair usually required?⚠ Follow only the manufacturer-backed checks listed on this page before replacing parts.
If the error keeps returning
Use the linked official manufacturer support source for additional model-specific guidance.
Official source
Troubleshooting information verified against manufacturer support documentation.
View manufacturer support page →Safety note:ApplianceSignal provides general troubleshooting information. Always follow the appliance manufacturer's safety instructions and disconnect power when required.