Bosch Oven Error Code E303
E303 is E302's close relation in the control module: the electronics' temperature — or the speed at which it is rising — is over the limit. The response is the same: elements off, fan to high speed, automatic recovery once cool, with the cooling fan as the usual root cause.
Common causes
- Cooling fan failing, letting the electronics' temperature climb too fast
- Blocked cabinet ventilation
- Control module temperature sensor drifting
What to check, in order
- Cancel the cycle and let the oven cool fully; the fault clears itself when the cavity temperature reaches about 212°F/100°C.
- Listen for the cooling fan running at high speed during the cool-down — silence points at the fan.
- Confirm the installation vents are unobstructed before using the oven again.
- Repeated E303 in ordinary baking, not just self-clean, means the fan or the module's sensor needs testing — book a technician.
Clear the code and test
- Fix what the checks above found first. Clearing the code without fixing the cause only brings it back.
- Plug the appliance back in and restore its water supply if it has one.
- Run the shortest programme and watch the point where the code appeared before.
- If the programme finishes with no code, the fault is cleared. If the code returns, write it down before calling a technician — it speeds up the diagnosis.
When to call a professional
Most cases are solved by the checks above. Book a technician if any of these apply:
- The code comes back after you have run the checks and a test cycle.
- You smell burning, see sparks or scorch marks, or the breaker trips.
- Water is leaking and you cannot stop it at the tap.
- The fix needs panels opened beyond what your manual describes, or a part tested with a meter, and you are not set up for that.
When you call, give the brand, the code E303, your model number (on a label inside the door or on the back) and the checks you already ran. It shortens the visit.
Parts that may be involved
Cooling fan motorControl module
Parts are model-specific. Find your model number first — usually on a label inside the door, on the door frame or on the back — and match the part to that number before ordering.
Questions people ask about E303
What does E303 mean on a Bosch oven?
E303 means: Electronics temperature too high or rising too fast (control module). E303 is E302's close relation in the control module: the electronics' temperature — or the speed at which it is rising — is over the limit. The response is the same: elements off, fan to high speed, automatic recovery once cool, with the cooling fan as the usual root cause.
Can I fix Bosch E303 myself?
Start yourself: the checks on this page cover the causes you can reach without opening the machine up. If they point to a faulty part, testing or replacing it is usually a technician job.
How do I clear Bosch E303?
Fix the cause first — clearing the code on its own brings it straight back. Then restore power and water, run the shortest programme, and watch the stage where the code appeared. If the programme finishes with no code, it is cleared.
Sources checked
- Bosch Home (US) owner support: dishwasher error codes
- Coolblue advice: Bosch and Siemens washing machine errors
The meaning and checks for this code were checked against the sources above in November 2026. Codes vary by model and region; if your manual lists a different meaning for your exact model, follow the manual.