E12 is connected with limescale buildup in the heat pump. Use the exact model number and the visible symptoms before deciding what the dishwasher needs.
E12 is connected with limescale buildup in the heat pump. Use the exact model number and the visible symptoms before deciding what the dishwasher needs.
Model compatibility: Bosch reuses codes across series and model years, so E12 may mean something different on another appliance or generation. Confirm this against your model’s documentation and record your full model number before acting.
Plain language
What this code means
The verified Bosch meaning for E12 is limescale buildup in the heat pump. Treat that wording as the technical anchor for this page. The displayed code narrows the system that needs attention, but the complete E-Nr and observed behavior are still important before a repair decision is made.
Signs
Symptoms you may notice
heating or drying performance may change
mineral residue may be more noticeable
the dishwasher may request attention before normal performance returns
the code can reappear if scale remains
Why it happens
Possible causes
mineral scale in the heat-pump path
hard-water buildup
water-softening maintenance that is no longer controlling scale effectively
Important safety warning. Stop use for leaking, electrical odor, smoke, or another unsafe condition.
Seeing this code on your Bosch appliance?
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