Thermador Oven H0 Error Code: Causes and Fixes
Quick answer: Heating relay check failed
What you’ll notice
Heating relay self-test failed; oven may not heat.
Thermador
Oven
Code H0
medium severity
Thermador models: Thermador professional ranges use Star Burners on gas models and an ExtraLow simmer feature. The oven temperature probe is at the rear cavity wall. Thermador wall ovens have a Soft Close door mechanism; if the oven door does not latch cleanly for self-clean, check whether the closer mechanism has disengaged.
Common causes
- Relay on the control board stuck open or closed
- Heater element disconnected
Step-by-step fix
- Power cycle.
- If the oven heats but H0 persists, the relay's self-test logic has a fault.
- If the oven does not heat, test the bake and broil elements for continuity.
Tools you may need
Multimeter
Prevention
- Use a surge protector.
When to stop DIY
A relay failure on the control board requires board replacement.
FAQ
What does H0 mean on Thermador oven?
H0 usually indicates: Heating relay check failed.
Can I keep using the appliance with H0?
Use caution. Severity is medium. A relay failure on the control board requires board replacement.
How long does this fix usually take?
Typical first-pass troubleshooting takes 15–30 minutes.