What to check first
Can I keep using it?
Stop for leak or water warnings
Do not keep running the appliance when water is visible, a leak warning is active, or water could reach wiring or controls.
- Safe next step
- Stop the cycle if safe, turn off water when appropriate, protect the floor, and avoid repeated resets until the leak source is understood.
- Stop when
- Water is near wiring, cabinetry is getting wet, the leak returns, or the source is not safely visible.
Electrical warning: stop and verify
Do not keep using the appliance if the code points to voltage, wiring, control power, burning smell, smoke, or a possible miswired supply.
- Safe next step
- Use only safe owner-level power checks, then involve a qualified technician or electrician when the source points to wiring or supply voltage.
- Stop when
- Breakers trip, lights dim, the appliance smells hot, wiring may be miswired, or the warning returns after a safe reset.
Safety boundaries
Safe first
- Match the exact brand, appliance type, and displayed code first.
- Use the model manual as the final authority for access steps.
- Disconnect power before any service-access step.
Do not do this
- Do not use other cycles as a workaround unless the manual allows it.
- Do not bypass locks, float switches, leak sensors, or other safety systems.
Common causes include
- Hard-water limescale build-up
- Heat pump efficiency reduced by mineral deposits
- Water softener salt or descaling maintenance overdue
Basic checks
- Review Bosch descaling guidance for the exact model.
- Check whether the dishwasher has a water softener function and salt indicator.
- Do not open heater or pump assemblies for descaling.
Reset or retry steps
- Retry only after following the model-safe descaling or maintenance guidance.
When to call a technician
- Call Bosch support if E12 returns after correct descaling.
- Call service if there are heat, smell, leak, or electrical symptoms.
FAQ
What does Bosch Dishwasher code E12 usually mean?
Usually indicates limescale build-up in the dishwasher heat pump.
Can I keep using the dishwasher with code E12?
Limit use to the owner-level checks described here and in the model manual. Stop using the appliance if the code returns, the appliance behaves abnormally, or a safety warning applies. Do not mix descaling chemicals or use non-approved cleaners.
When should I call a technician for Bosch E12?
Call Bosch support if E12 returns after correct descaling. Call service if there are heat, smell, leak, or electrical symptoms.