Bosch dishwasher E12 error
Usable, but not working properly
Limescale and grease have built up on the heating surfaces to the point where the machine reports that it needs descaling before it can heat water reliably. The machine is in a hard water area and has been run for a long period without descaling is the most common cause.
- Difficulty
- DIY
- Time needed
- About 120 min
- Checks
- 5 steps
The same fault is shown as E2060, E:20-60 on some Bosch series, depending on the display and the model year.
Before you start
- Never use table salt or rock salt in the softener reservoir. The anti-caking agents in them damage the resin and the fault gets worse rather than better.
- Descaler is acidic. Follow the dose on the pack, keep it off your skin, and do not mix it with detergent in the same cycle.
What it means
Limescale and grease have built up on the heating surfaces to the point where the machine reports that it needs descaling before it can heat water reliably.
Most likely causes
Ordered from most to least common, with what each one looks like:
| Cause | How likely | What you would see |
|---|---|---|
| The machine is in a hard water area and has been run for a long period without descaling | high | A chalky white film has formed on the tub walls and on glassware coming out of the machine |
| The salt reservoir has been left empty, so the built-in softener has not been treating the incoming water | high | The salt refill light has been lit and ignored, or the reservoir is dry when the cap is unscrewed |
| The water hardness setting was never adjusted to match the local supply when the machine was installed | medium | The machine is in a hard water district but is still on its factory hardness setting |
| Only short low-temperature programmes are used, so grease is never fully rendered and bakes onto the heater | low | The machine is almost always run on eco or quick cycles and the tub smells stale |
Fix steps
Tools needed
- Funnel
-
Unscrew the salt reservoir cap in the base of the tub and check whether there is any dishwasher salt left in it.
Expected result You can see salt or brine rather than an empty chamber. If it does not, go to step 2.
-
Top the reservoir up with coarse dishwasher salt, never table salt, and wipe up any spillage from the tub floor before closing the cap firmly.
Expected result The reservoir is full, the cap is tight and no loose granules remain in the tub.
-
Look up the water hardness for your postcode with your water supplier and set the machine's hardness level to match, following the setting procedure in your manual.
Expected result The stored hardness figure reflects the actual supply rather than the factory default.
-
Empty the machine completely, place a proprietary dishwasher descaler in the tub and run the hottest and longest programme available.
Expected result The cycle finishes with visibly cleaner tub walls and less film on the heater area. If it does not, go to step 5.
-
If the film is heavy, repeat the descaling cycle a second time rather than trying to scrape deposits off by hand.
Expected result The code clears and normal programmes complete with properly heated water.
Parts needed
| Part | Part number | Typical cost |
|---|---|---|
| Dishwasher descaler | Varies by model | Varies by supplier |
| Coarse dishwasher salt | Varies by model | Varies by supplier |
When to call a technician
Call a qualified technician if you work through every step above and the code comes back, if you find water where it should not be, or if any part of the job needs the machine powered up with panels removed. A repeat fault after a correct repair usually points at the control board rather than the part you replaced.
Common questions
What does E12 mean on a Bosch dishwasher?
Limescale and grease have built up on the heating surfaces to the point where the machine reports that it needs descaling before it can heat water reliably. The machine is in a hard water area and has been run for a long period without descaling is the most common reason for it.
Can I keep using the dishwasher?
You can usually still run the machine, but it will not be working correctly and the fault will keep coming back until it is fixed.
Is this something I can fix myself?
Yes, for most people. The checks below need funnel and take about 120 minutes.
Models this applies to
- SMS All codes for this model
- SMV All codes for this model
- SMI All codes for this model
- SHP All codes for this model
- SHE All codes for this model
Related codes on the same machines
- E15 Water has collected in the tray underneath the dishwasher and a float in that tray has tripped the leak protection system, which shuts the machine down and runs the drain pump to keep the leak from spreading.
- E18 The machine asked for water and not enough arrived in the time it allows, so it stopped the cycle rather than washing without a proper fill.
- E21 The circulation pump that drives water up to the spray arms is reported as blocked, so the machine stops rather than running the motor against an obstruction.
- E22 The filters in the base of the tub are blocked enough to starve the circulation pump, or the filter assembly is not locked into place, so the machine cannot move water round the wash arms properly.
- E23 The machine has detected a fault in the waste water pump circuit.
- E24 The dishwasher tried to pump the water out and the level in the tub did not drop, so it stopped mid-cycle with dirty water still standing in the bottom.