Bosch E09: Heating Element Circuit Open
High severity
E09 tells you Bosch's control board can no longer detect an electrical path through the heating element, so the dishwasher has effectively stopped heating water.
Dishes come out of a full cycle still greasy or filmed with detergent residue, glasses stay spotted, and if you touch the water partway through a cycle it feels lukewarm at best. The display shows E09 either right away or only after a cycle finishes without ever getting properly hot.
Applies to: Bosch dishwashers with an electronic control and a resistive heating element (most 300/500/800 series models).
What it means
The control board has detected an open circuit in the heating element, meaning it has lost electrical continuity and cannot heat water at all.
An open circuit just means electricity no longer has anywhere to flow — somewhere along the heater's wiring or in the element itself, the path is broken, so no amount of resetting restores heat until that break is physically repaired.
Common causes
A handful of things can break that circuit, most tied to age or water hardness rather than a manufacturing defect:
- Heating element burned out, corroded, or physically damaged over time
- Mineral/limescale buildup from hard water causing the element to overheat and fail
- A failed water temperature sensor or thermal cut-off feeding bad data to the control board
- Wiring or connector corrosion between the element and the control board
What you can check yourself
There isn't much a homeowner can safely do here beyond ruling out a one-off glitch and reducing strain on the element going forward:
- Power-cycle the dishwasher at the breaker for a few minutes and run a short cycle to confirm the code is not a one-off glitch
- Run a hot water tap near the dishwasher briefly before starting a cycle so it fills with hot rather than cold water, which reduces load on the element
- Descale the interior with a dishwasher-safe descaler if you have hard water and haven't done this in a while
Call a professional when
E09 involves mains-voltage heating components inside the tub. Because this is an electrical safety issue, Bosch and most repair techs recommend booking a professional visit rather than opening up the heater circuit yourself.
Related
- Bosch dishwasher codes hub
- Bosch E01 — control fault, sometimes heating-circuit related
- Bosch E27 — low supply voltage shutdown
- Dishwasher Not Heating, Drying, or Sanitizing