E09 means the control board has detected an open circuit in the heater — the heating element has lost electrical continuity and cannot warm the wash water at all. Expect cold dishes, unusually long cycles, and no drying at the end of the programme.
What E09 means
Bosch dishwashers heat water electrically as part of the wash cycle. E09 fires when the control board sends power to the heater circuit and gets no continuity back — the circuit is genuinely open rather than just underperforming.
Common causes
| Cause | How likely | Notes |
|---|---|---|
| Failed or weak heater/heat pump assembly | Common | The element itself has burned out |
| Corroded heater terminals | Occasional | Connection point has degraded over time |
| High-limit or NTC temperature sensor fault | Occasional | Sensor rather than heater is at fault |
| Heater relay fault on the main control board | Less common | Board-level rather than heater-level issue |
| Wiring fault in the heater circuit | Less common | Damaged or loose connection along the harness |
What you can check
- Power cycle the machine
Turn the dishwasher off at the breaker for about five minutes, then restore power and run a cycle. If E09 returns, the heater circuit needs proper diagnosis.
On most Bosch dishwashers, the heating element is built into the circulation pump — replacing the heater means replacing the entire pump assembly. Beyond a power cycle, this fault needs a technician with the right diagnostic and replacement parts.
When to call a professional
If a power reset does not clear E09, have a technician test the heater/heat pump assembly, the high-limit sensor and the heater relay on the control board before ordering parts — on most models the fix is a full pump assembly replacement.
Stop and call a qualified appliance technician or electrician if you find scorched or melted wiring, smell burning, see water that has reached electrical components, or if the fault returns immediately after a repair. Never bypass a safety device — thermal fuses, door interlocks and flood switches fail for a reason, and defeating one converts a broken appliance into a fire or flood risk.
