Bosch Factory Service ManualFault Code: Er3

Bosch Range/Oven Error Code Er3: Oven Cavity High-Temperature Limit Tripped

The safety high-limit thermal cutoff switch has opened or the RTD oven temperature sensor detects cavity temperatures exceeding 650°F during normal baking.

Target Appliance

oven range

OEM Certified Technical Diagnostic Tree

Diagnostic Tool Required

Digital Multimeter

Measure Ohms resistance, continuity & line voltage.

Triage Complexity

Advanced Diagnostic

4 Sequential manufacturer inspection branches.

Sequential Factory Diagnostic Tree

Perform each diagnostic step in order. Disconnect electrical power and turn off utility shutoffs before inspecting wiring or internal mechanical assemblies.

Step 1: Physical & Electrical InspectionMultimeter & Visual

Action: Disconnect electrical power, allow oven to cool completely, and locate the thermal safety high-limit switch on back chassis.

Bench Test: Measure continuity across high-limit switch terminals with a digital multimeter.

Expected Standard: 0 ohms continuity (closed circuit) at room temperature.

If Failed / Out of Spec:

Switch tripped or open. Replace thermal high-limit safety cutoff (00613292).

If Passed:

Proceed to Step 2.

Step 2: Physical & Electrical InspectionMultimeter & Visual

Action: Test resistance across the stainless oven temperature RTD sensor probe inside upper rear cavity.

Bench Test: Unplug sensor harness at rear of oven and measure resistance at room temperature (77°F).

Expected Standard: Approximately 1,080 to 1,090 ohms (1.08k–1.09k Ω) at 77°F; ~1,650 ohms at 350°F.

If Failed / Out of Spec:

Resistance out of specification (open or shorted). Replace oven RTD temperature sensor (00627375).

If Passed:

Proceed to Step 3.

Step 3: Physical & Electrical InspectionMultimeter & Visual

Action: Inspect the electronic cooling fan blower motor mounted above the oven cavity.

Bench Test: Check cooling fan blower blades for physical binding and measure motor winding resistance.

Expected Standard: Fan spins freely; motor winding reads 40 to 60 ohms.

If Failed / Out of Spec:

Blower stalled or motor burned out. Replace cavity cooling fan motor (00657921).

If Passed:

Proceed to Step 4.

Step 4: Physical & Electrical InspectionMultimeter & Visual

Action: Inspect heating element control relays on the main power relay board.

Bench Test: Check if bake or broil relay contacts are welded closed, providing runaway continuous heat.

Expected Standard: Relay contacts open when de-energized; infinity resistance across contacts.

If Failed / Out of Spec:

Welded relay contacts. Replace main power relay control board (12009843).

If Passed:

Reassemble and verify temperature calibration in service mode.

Verified OEM Replacement Parts

Cross-referenced factory part numbers for Bosch oven-range error code Er3. Always replace defective components with authentic OEM parts to maintain UL safety certification.

Component Name	OEM Part Number	Manufacturer	Status
Oven Cavity RTD Temperature Sensor Probe	`00627375`	Bosch	Direct Fit OEM
Thermal High-Limit Safety Cutoff Switch	`00613292`	Bosch	Direct Fit OEM
Upper Cavity Cross-Flow Cooling Blower Fan	`00657921`	Bosch	Direct Fit OEM

Need Local Diagnostic Assistance?

Connect with a Certified Bosch Technician in Your Area

If multimeter testing reveals an internal short, locked motor, or fried control board, let an experienced local technician complete the repair with certified OEM replacement parts.

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Frequently Asked Questions: Bosch Er3

What causes Bosch oven-range error code Er3?

The safety high-limit thermal cutoff switch has opened or the RTD oven temperature sensor detects cavity temperatures exceeding 650°F during normal baking.

Can I reset the Er3 code by unplugging the oven-range?

While disconnecting power for 5 minutes may temporarily clear the display control memory, the Er3 code will reoccur once the microcontroller detects the mechanical or electrical fault again.

What OEM replacement parts are required for Bosch Er3?

Common OEM replacement components include: Oven Cavity RTD Temperature Sensor Probe (OEM #00627375), Thermal High-Limit Safety Cutoff Switch (OEM #00613292), Upper Cavity Cross-Flow Cooling Blower Fan (OEM #00657921).