Can I fix Bosch code E12 myself?

Start with these safe checks: Run a descaling cycle with a dishwasher descaler. If your model has a water softener, keep the softening salt topped up. If E12 returns after descaling, contact support.

When should I call a technician for code E12?

If E12 returns after descaling, contact support. Unplug it or switch the breaker off before you remove any panel. Don't test or replace wiring, control boards, heating elements or motors under power. If you see scorching, smell burning, or the breaker trips again, leave it off and call a qualified appliance technician or electrician.

Bosch Dishwasher Error Code E12 / E:12: Limescale in the…

What E12 means

Limescale has built up in the circulation pump's heater. The dishwasher needs to be descaled.

Also shown as: E:12, depending on the model.

Likely causes

Hard water
No softening salt (on models with a water softener)

Safe first checks

Run a descaling cycle with a dishwasher descaler.
If your model has a water softener, keep the softening salt topped up.

When to stop

If E12 returns after descaling, contact support.

Checked against: Bosch USA: Bosch dishwasher error codes troubleshooting guide. Codes can differ by model and year, so confirm with your owner's manual.