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e12
Moderate
Bosch · Dishwashers
Limescale buildup - descaling needed
Quick Answer
Error code E12 on your Bosch Dishwashers means: Limescale buildup - descaling needed. This is usually fixable — see the step-by-step guide below.
Affected Models
Applies to all models
SHXM4AY55NSHEM3AY55NSHP95CM5NSHPM65Z55NSGX78B55UCSHXM88Z75NSHXM78Z55NSHX78CM5NSHP878ZD5NSHPM88Z75NSHPM78Z55NSHEM78Z55NSHX89PW75NSHV89PW73NSHE89PW75N
Likely Causes
  1. Excessive limescale accumulation on heating element and internal components
  2. Hard water area without regular descaling maintenance
  3. Water softener not functioning (on equipped models)
  4. Prolonged use without descaling
How to Fix It
1
Purchase a Bosch-approved dishwasher descaling agent.
2
Remove all dishes and racks from the dishwasher.
3
Place the descaling agent in the detergent dispenser or bottom of the tub as directed.
4
Run a hot water cycle (Heavy or Intensive) to descale the machine.
5
Repeat monthly in hard water areas to prevent recurrence.
6
If the error persists after descaling, the heating element may be damaged and need replacement.
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
Dishwasher descaling agent
Related Error Codes
E0E01E02E03E04
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