Thermador · Dishwasher error code

E12Limescale in heat pump

Cross-checked Power off, standard tools

Unlock what this code means, its causes, tests and parts

Full library + AI assistant for $34.90, one time.

Get lifetime access

OnCall Tech is a reference tool for trained technicians and can make mistakes. Always disconnect power and confirm with the manufacturer's documentation before you work.

Related diagnostic guides

Guide · Dishwasher

Dishwasher not heating water

Confirm the supply water is hot first, then test the heater (or Bosch heat pump heater), the high-limit and the thermistor. If all test good, suspect the heater relay on the control.

5 steps ~60 minmoderate

More Thermador dishwasher codes

Thermador · Dishwasher

E14

Flow meter / fill fault

Single source

Thermador · Dishwasher

E15

Water in base / leak protection active

Cross-checked

Thermador · Dishwasher

E16 / E17

Water inflow problem

Single source

Thermador · Dishwasher

E23

Drain pump blocked or faulty

Single source

Thermador · Dishwasher

E24

Drain failure

Cross-checked

Thermador · Dishwasher

E25

Drain pump / drain path blocked

Single source
Thermador dishwasher error E12: Limescale in heat pump · OnCall Tech