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Bosch · HMB50152UC 500 Series 30 in Built-In Microwave

Bosch HMB50152UC 500 Series 30 in Built-In Microwave E4 Error Fix: Door Switch / Interlock Failure

One or more door interlock switches has failed. Microwaves use 2-3 door switches as a critical safety system — all switches must indicate the door is closed before the magnetron will energize. Check the door latch assembly and all door switch alignment. Test each door switch for proper continuity with a multimeter. Replace any defective switch immediately. **Important:** The monitor switch (shorting switch) is a safety device that blows the line fuse if the primary switches fail while the door is open. If the microwave blows fuses repeatedly, the monitor switch and primary interlock switches need inspection.

High severity2 fixes available✨ Free fix available

Quick Answer

Error E4 on the Bosch HMB50152UC 500 Series 30 in Built-In Microwave means: Door Switch / Interlock Failure. The top-ranked community fix is “Test and Replace Door Interlock Switches” (hard difficulty, ~45 min, DIY cost: $15-$30). 2 community-ranked fixes available below.

Published February 2026 · 2 fixes · microwave

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 microwave repairs can be done safely at home, consider hiring a qualified technician if:

This is a high severity error — continued use may cause damage or a safety hazard
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 E4

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

HMC80152UC 800 Series 30 in Convection Speed Microwave

microwave · 2 fixes

HMC80252UC 800 Series 30 in Speed Microwave Oven

microwave · 2 fixes

HMD8451UC 800 Series 24 in Drawer Microwave

microwave · 2 fixes

HMV3053U 300 Series 30 in Over-the-Range Microwave

microwave · 1 fix

HMV5053U 500 Series 30 in Over-the-Range Microwave

microwave · 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

SHPM78Z55N 24 in 500 Series Top Control 44 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 HMB50152UC 500 Series 30 in Built-In Microwave Error Codes

Magnetron Failure — Not Heating

2 fixes

Humidity / Steam Sensor Failure

2 fixes

Temperature Sensor / Thermostat Error

2 fixes

Control Panel / Touchpad Error

2 fixes

Sensor Error — Humidity Sensor

2 fixes

People Also Ask About Bosch HMB50152UC 500 Series 30 in Built-In Microwave Error E4

What does error code E4 mean on a Bosch HMB50152UC 500 Series 30 in Built-In Microwave?

Error code E4 on the Bosch HMB50152UC 500 Series 30 in Built-In Microwave means: Door Switch / Interlock Failure. One or more door interlock switches has failed. Microwaves use 2-3 door switches as a critical safety system — all switches must indicate the door is closed before the magnetron will energize. Check the door latch assembly and all door switch alignment. Test each door switch for proper continuity with a multimeter. Replace any defective switch immediately. **Important:** The monitor switch (shorting switch) is a safety device that blows the line fuse if the primary switches fail while the door is open. If the microwave blows fuses repeatedly, the monitor switch and primary interlock switches need inspection.

How do I fix error code E4 on my Bosch HMB50152UC 500 Series 30 in Built-In Microwave?

The most successful fix is "Test and Replace Door Interlock Switches" (hard difficulty, ~45 minutes). Estimated DIY cost: $15-$30. HomeMD has 2 community-ranked fixes for this error.

Is error code E4 on a Bosch HMB50152UC 500 Series 30 in Built-In Microwave serious?

This error is rated high severity. You should address it promptly — continued use could cause damage or safety concerns.

Can I fix Bosch HMB50152UC 500 Series 30 in Built-In Microwave error E4 myself?

Yes — the top-ranked community fix ("Test and Replace Door Interlock Switches") is rated hard difficulty and takes about 45 minutes. Tools needed: T20 Torx screwdriver, Multimeter, Needle-nose pliers.

How much does it cost to repair Bosch HMB50152UC 500 Series 30 in Built-In Microwave error E4?

DIY cost: $15-$30. 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 HMB50152UC 500 Series 30 in Built-In Microwave have?

The Bosch HMB50152UC 500 Series 30 in Built-In Microwave has 5 other known error codes, including: E1 (Magnetron Failure — Not Heating), E2 (Humidity / Steam Sensor Failure), E3 (Temperature Sensor / Thermostat Error), E5 (Control Panel / Touchpad Error), SE (Sensor Error — Humidity Sensor).

Which other Bosch models have the E4 error?

Error code E4 also appears on 25 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 19 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 HMB50152UC 500 Series 30 in Built-In Microwave have?

The Bosch HMB50152UC 500 Series 30 in Built-In Microwave has 5 other known error codes:

E1 — Magnetron Failure — Not Heating (2 fixes)
E2 — Humidity / Steam Sensor Failure (2 fixes)
E3 — Temperature Sensor / Thermostat Error (2 fixes)
E5 — Control Panel / Touchpad Error (2 fixes)
SE — Sensor Error — Humidity Sensor (2 fixes)

Which other Bosch models have the E4 error?

Error code E4 also appears on 25 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
HMC80152UC 800 Series 30 in Convection Speed Microwave (microwave) · 2 fixes
HMC80252UC 800 Series 30 in Speed Microwave Oven (microwave) · 2 fixes
HMD8451UC 800 Series 24 in Drawer Microwave (microwave) · 2 fixes
HMV3053U 300 Series 30 in Over-the-Range Microwave (microwave) · 1 fix
HMV5053U 500 Series 30 in Over-the-Range Microwave (microwave) · 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
SHPM78Z55N 24 in 500 Series Top Control 44 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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