# E12 — Appliance fault and error codes

For E12, brand is Bosch; appliance type is Dishwasher; meaning is There is limescale build-up in the heat pump, verified against its source on 2026-08-04.

- **Brand:** Bosch
- **Appliance type:** Dishwasher
- **Error code:** E12
- **Meaning:** There is limescale build-up in the heat pump.

## What the source says

> See more Error Code E12 There is limescale build-up in the heat pump. The dishwasher needs to be descaled. The Bosch descaler can be used to descale your dishwasher.

## Source

- https://www.bosch-home.com/us/owner-support/dishwashers/error-codes

Last verified: 2026-08-04. Review by: 2027-08-04.
Part of [Appliance fault and error codes](https://referencesource.org/appliance-fault-error-codes/).