Bosch Dishwasher E12 error code
Mineral scale has built up on the heating element, usually from hard water. The machine flags this so you descale before cleaning performance or efficiency drops.
Last updated: September 30, 2026
What causes the E12 error?
- Hard water deposits accumulating with regular use
- No or irregular descaling routine
- Water softener salt not used on models with a softener
How to fix Bosch E12 — step by step
Work through these in order, from simplest and safest first. Stop as soon as the code clears.
- Descale the dishwasher
Run the Bosch descaler according to its instructions to dissolve hard-water deposits from the heat pump. - Use softening salt
If your model has a water softener, keep it topped up with softening salt; check your owner's manual for how to add it. - Descale regularly
Make descaling a routine, especially in hard-water areas, to stop E12 from returning.
When to call a technician
- The code returns after descaling
- Heating or cleaning performance stays poor after descaling
Frequently asked questions
How do I prevent E12 on my Bosch dishwasher?
Descale regularly and use softening salt if your model supports it; hard water areas need this more often.
Sources
Every meaning and fix above was checked against official manufacturer documentation:
FixCode provides general troubleshooting information only — not professional repair advice. If you are unsure about any step, stop and call a qualified technician. Repairs done incorrectly can be dangerous and may void your warranty.
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