FixByModel
E09

Bosch E09: Heating element / flow heater defective

The control detected a fault in the heating element (flow-through heater), so the dishwasher cannot heat the water. Bosch treats this as a component failure that generally needs professional repair.

May need a technician

By the FixByModel editorial team · Verified 2026-09 · Researched against manufacturer support & repair references (below)

Most likely causes

  1. Failed or open-circuit heating element (flow heater) — most common
  2. Scale/mineral buildup on the heater from hard water causing it to burn out
  3. Corroded heater terminals or damaged heater wiring
  4. On models with regenerating salt, a dirty salt sensor giving false readings
  5. Control board fault in the heater circuit (rare)
Before you start — unplug the appliance and turn off the water supply. You'll be working near water and electrical parts, and drained water can be hot. If a step involves the pump, wiring, or opening the cabinet and you're unsure, stop and call a qualified technician.

Step-by-step fix

1Power-cycle firstSwitch off at the breaker for about 30 seconds and restart, in case the fault was a transient glitch.
2Check the salt sensorIf the salt indicator is also lit, make sure the dishwasher salt sensor and reservoir are clean, as dirt can cause a false trigger.
3Book a technicianBosch advises not to attempt this repair yourself; a qualified engineer should diagnose and replace the heater safely.
4Replace the heater assemblyThe flow heater is integrated into the sump/pump assembly, so professional replacement involves removing the base plate and swapping the heater unit.

Still showing E09?

If you’ve worked through every step and E09 keeps returning, an internal part likely needs testing and replacement. That’s a job for a qualified appliance technician, who can measure the suspect part against the service-manual spec before replacing it.

Which models this applies to

Bosch dishwashers. Bosch dishwashers using an integrated flow-through heater (the sealed heater/sump/pump design used across current Bosch dishwasher ranges).

FAQ

What does Bosch E09 mean?

Heating element / flow heater defective. The control detected a fault in the heating element (flow-through heater), so the dishwasher cannot heat the water. Bosch treats this as a component failure that generally needs professional repair.

What causes Bosch E09?

The most likely cause is failed or open-circuit heating element (flow heater) — most common. Other causes include Scale/mineral buildup on the heater from hard water causing it to burn out; Corroded heater terminals or damaged heater wiring; On models with regenerating salt, a dirty salt sensor giving false readings; Control board fault in the heater circuit (rare).

Can I fix Bosch E09 myself?

Some checks are DIY, but this code often points to an internal component, so it may need a qualified technician.