Bosch E3 error code

What it means

E3 means indoor fan speed error. In plain English, a fan is not moving at the speed the control expects, so the system may stop to protect the coil, compressor, or inverter electronics.

Urgency

Likely causes

1. Fan blade is blocked, rubbing, or not spinning freely
2. Fan motor or bearing has failed
3. Fan motor connector or harness is loose or damaged
4. Control board fan-drive circuit fault

Homeowner fix

Turn the system off. Clear only loose, obvious debris outside the cabinet or from the user-accessible intake area; do not remove panels. Reset once if safe.

When to call a pro

Call a licensed HVAC technician if E3 returns after one safe reset or the condition will not clear. Tell them the official source lists E3 as Indoor fan speed error.

Repair vs replace

Fan and board faults are normally repairable. Compare repair with replacement only if an older unit also needs major inverter, compressor, or refrigerant work.

• Bosch Climate 5000 A/B legacy R-410A 9,000 BTU Regular (BMS500-AAU009-1AHWXB / BMS500-AAS009-1CSXRA)

  Climate 5000 A/B legacy R-410A

• Bosch Climate 5000 A/B legacy R-410A 12,000 BTU Regular (BMS500-AAU012-1AHWXB / BMS500-AAS012-1CSXRA)

  Climate 5000 A/B legacy R-410A

• Bosch Climate 5000 Gen 4 R-454B 6,000 BTU Regular (BMS500-AAU006-1AHWXD / BMS500-AAS009-1CSXRD)

  Climate 5000 Gen 4

• Bosch Climate 5000 Gen 4 R-454B 9,000 BTU Max Performance (BMS500-AAU009-1AHWXD / BMS500-AAS009-1CSXHD)

  Climate 5000 Gen 4

For your technician

Technician note: verify fan rotation, obstruction, motor windings/drive voltage, feedback signal, harness, and PCB output. Source: Bosch Climate 5000 G2 A/B IDU service manual Table 14 and ODU service manual Table 12; supporting diagnosis sections where listed; Table 12/Table 14; Diagnosis E3/F5. Page context: Bosch maps this display to the Climate 5000 A/B legacy R-410A line; source: Bosch Home Comfort official Climate 5000 G2/A-B Ductless AC-HP IDU and ODU Service Manuals, wall-mounted error-code tables and diagnosis sections; display convention: match the letter E and three marker exactly before comparing neighboring codes.

Which systems show it

Climate 5000 A/B legacy R-410A

Related troubleshooting

Use the symptom guide alongside the exact display code if the unit is flashing, cycling, or showing comfort symptoms.

Related codes

Source

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