🍽️Dishwasher

E12

Bosch · SHPM78Z55N 24 in 500 Series Top Control 44 dBA

Bosch SHPM78Z55N 24 in 500 Series Top Control 44 dBA E12 Error Fix: Calcification / Scale Buildup

The dishwasher has detected excessive calcification or mineral scale buildup. Hard water deposits have accumulated on the heating element, sensors, or spray arms, reducing efficiency. Run a descaling cycle using a dishwasher-approved descaler or citric acid. Clean the spray arms — remove them and clear all spray holes of mineral deposits. Check the rinse aid dispenser and ensure it is filled. In hard water areas, consider using a water softener. Repeated E12 codes indicate the water hardness setting may need adjustment.

Low severity2 fixes available

Quick Answer

Error E12 on the Bosch SHPM78Z55N 24 in 500 Series Top Control 44 dBA means: Calcification / Scale Buildup. The top-ranked community fix is “Adjust Water Hardness Setting and Replace Scale-Affected Components” (medium difficulty, ~45 min, DIY cost: $0-$20). 2 community-ranked fixes available below.

Published February 2026 · 2 fixes · dishwasher

Content is based on manufacturer service documentation, community repair experience, and OEM technical bulletins. Always verify with your owner's manual.Learn about our editorial standards.

When to Call a Professional

While many dishwasher repairs can be done safely at home, consider hiring a qualified technician if:

The repair involves electrical wiring, gas lines, or refrigerant
You've tried the top-ranked fix and the error persists
You smell gas, see sparking, or notice water leaking
The repair requires specialized tools you don't have
Your appliance is still under manufacturer warranty

Average professional repair cost for this issue: $120-$180.

Other Bosch Models with Error E12

B09IB81NSP 24 in 800 Series Glass Door Bottom Freezer

refrigerator · 2 fixes

B11CB81SSS 24 in 800 Series Counter Depth Bottom Freezer

refrigerator · 2 fixes

B21CL81SNS 36 in 800 Series Counter Depth 4-Door French Door

refrigerator · 2 fixes

B30IR900SP 30 in Benchmark Built-In All Refrigerator

refrigerator · 2 fixes

B36CL80SNS 36 in 800 Series French Door with VitaFreshPro

refrigerator · 2 fixes

B36CT80SNS 36 in 800 Series French Door Counter Depth

refrigerator · 2 fixes

B36FD50SNS 36 in 500 Series French Door with Quick IcePro

refrigerator · 2 fixes

B36IT80SNS 36 in Benchmark Built-In French Door

refrigerator · 2 fixes

SHE3AR75UC 24 in 100 Series Front Control 50 dBA

dishwasher · 2 fixes

SHE53C85N 24 in 300 Series Front Control 46 dBA

dishwasher · 2 fixes

SHP65CM5N 24 in 500 Series Pocket Handle 44 dBA

dishwasher · 2 fixes

SHP65TL5UC 24 in 500 Series Bar Handle 44 dBA with AutoAir

dishwasher · 2 fixes

SHP878ZD5N 24 in 800 Series Pocket Handle 42 dBA

dishwasher · 2 fixes

SHPM88Z75N 800 Series Dishwasher

dishwasher · 2 fixes

SHS53CD5N 24 in 300 Series Scoop Handle 46 dBA

dishwasher · 2 fixes

SHS863WD5N 24 in 300 Series Top Control 46 dBA

dishwasher · 2 fixes

SHV68TL3UC 24 in 800 Series Panel Ready 42 dBA

dishwasher · 2 fixes

SHX78CM5N 24 in 800 Series Bar Handle 42 dBA with CrystalDry

dishwasher · 2 fixes

SPE68B55UC 18 in 800 Series ADA Compact 44 dBA

dishwasher · 2 fixes

Other Bosch SHPM78Z55N 24 in 500 Series Top Control 44 dBA Error Codes

No Fault Codes Recorded

2 fixes

Heating Problem

2 fixes

E13

Water Heating Timeout

2 fixes

E14

Flow Meter / Water Sensor Error

2 fixes

E15

Water in Base Pan — AquaStop Activated

2 fixes

E16

Unauthorized Water Fill Detected

2 fixes

E17

Over-Fill Level Exceeded

2 fixes

E18

Inlet Valve Not Closing Properly

2 fixes

People Also Ask About Bosch SHPM78Z55N 24 in 500 Series Top Control 44 dBA Error E12

What does error code E12 mean on a Bosch SHPM78Z55N 24 in 500 Series Top Control 44 dBA?

Error code E12 on the Bosch SHPM78Z55N 24 in 500 Series Top Control 44 dBA means: Calcification / Scale Buildup. The dishwasher has detected excessive calcification or mineral scale buildup. Hard water deposits have accumulated on the heating element, sensors, or spray arms, reducing efficiency. Run a descaling cycle using a dishwasher-approved descaler or citric acid. Clean the spray arms — remove them and clear all spray holes of mineral deposits. Check the rinse aid dispenser and ensure it is filled. In hard water areas, consider using a water softener. Repeated E12 codes indicate the water hardness setting may need adjustment.

How do I fix error code E12 on my Bosch SHPM78Z55N 24 in 500 Series Top Control 44 dBA?

The most successful fix is "Adjust Water Hardness Setting and Replace Scale-Affected Components" (medium difficulty, ~45 minutes). Estimated DIY cost: $0-$20. HomeMD has 2 community-ranked fixes for this error.

Is error code E12 on a Bosch SHPM78Z55N 24 in 500 Series Top Control 44 dBA serious?

This error is rated low severity. It is generally not urgent and can often be resolved with a simple DIY fix.

Can I fix Bosch SHPM78Z55N 24 in 500 Series Top Control 44 dBA error E12 myself?

Yes — the top-ranked community fix ("Adjust Water Hardness Setting and Replace Scale-Affected Components") is rated medium difficulty and takes about 45 minutes. Tools needed: T20 Torx screwdriver, Phillips screwdriver, Multimeter.

How much does it cost to repair Bosch SHPM78Z55N 24 in 500 Series Top Control 44 dBA error E12?

DIY cost: $0-$20. Professional repair typically costs $120-$180. Many homeowners save money by trying the top-ranked community fix first.

What other error codes does the Bosch SHPM78Z55N 24 in 500 Series Top Control 44 dBA have?

The Bosch SHPM78Z55N 24 in 500 Series Top Control 44 dBA has 8 other known error codes, including: E0 (No Fault Codes Recorded), E1 (Heating Problem), E13 (Water Heating Timeout), E14 (Flow Meter / Water Sensor Error), E15 (Water in Base Pan — AquaStop Activated), and 3 more.

Which other Bosch models have the E12 error?

Error code E12 also appears on 19 other Bosch models: B09IB81NSP 24 in 800 Series Glass Door Bottom Freezer, B11CB81SSS 24 in 800 Series Counter Depth Bottom Freezer, B21CL81SNS 36 in 800 Series Counter Depth 4-Door French Door, B30IR900SP 30 in Benchmark Built-In All Refrigerator, B36CL80SNS 36 in 800 Series French Door with VitaFreshPro, B36CT80SNS 36 in 800 Series French Door Counter Depth, and 13 more. The fix may vary by model, so check each model's specific page for tailored repair steps.

What other error codes does the Bosch SHPM78Z55N 24 in 500 Series Top Control 44 dBA have?

The Bosch SHPM78Z55N 24 in 500 Series Top Control 44 dBA has 8 other known error codes:

E0 — No Fault Codes Recorded (2 fixes)
E1 — Heating Problem (2 fixes)
E13 — Water Heating Timeout (2 fixes)
E14 — Flow Meter / Water Sensor Error (2 fixes)
E15 — Water in Base Pan — AquaStop Activated (2 fixes)
E16 — Unauthorized Water Fill Detected (2 fixes)
E17 — Over-Fill Level Exceeded (2 fixes)
E18 — Inlet Valve Not Closing Properly (2 fixes)

Which other Bosch models have the E12 error?

Error code E12 also appears on 19 other Bosch models:

B09IB81NSP 24 in 800 Series Glass Door Bottom Freezer (refrigerator) · 2 fixes
B11CB81SSS 24 in 800 Series Counter Depth Bottom Freezer (refrigerator) · 2 fixes
B21CL81SNS 36 in 800 Series Counter Depth 4-Door French Door (refrigerator) · 2 fixes
B30IR900SP 30 in Benchmark Built-In All Refrigerator (refrigerator) · 2 fixes
B36CL80SNS 36 in 800 Series French Door with VitaFreshPro (refrigerator) · 2 fixes
B36CT80SNS 36 in 800 Series French Door Counter Depth (refrigerator) · 2 fixes
B36FD50SNS 36 in 500 Series French Door with Quick IcePro (refrigerator) · 2 fixes
B36IT80SNS 36 in Benchmark Built-In French Door (refrigerator) · 2 fixes
SHE3AR75UC 24 in 100 Series Front Control 50 dBA (dishwasher) · 2 fixes
SHE53C85N 24 in 300 Series Front Control 46 dBA (dishwasher) · 2 fixes
SHP65CM5N 24 in 500 Series Pocket Handle 44 dBA (dishwasher) · 2 fixes
SHP65TL5UC 24 in 500 Series Bar Handle 44 dBA with AutoAir (dishwasher) · 2 fixes
SHP878ZD5N 24 in 800 Series Pocket Handle 42 dBA (dishwasher) · 2 fixes
SHPM88Z75N 800 Series Dishwasher (dishwasher) · 2 fixes
SHS53CD5N 24 in 300 Series Scoop Handle 46 dBA (dishwasher) · 2 fixes
SHS863WD5N 24 in 300 Series Top Control 46 dBA (dishwasher) · 2 fixes
SHV68TL3UC 24 in 800 Series Panel Ready 42 dBA (dishwasher) · 2 fixes
SHX78CM5N 24 in 800 Series Bar Handle 42 dBA with CrystalDry (dishwasher) · 2 fixes
SPE68B55UC 18 in 800 Series ADA Compact 44 dBA (dishwasher) · 2 fixes

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