Bosch Refrigerator E01 & E02 Error Code Repair in Port St. Lucie

Quick symptom overview

Bosch 800 Series, Benchmark, and 500 Series French door and built-in refrigerators display E01 (Fresh Food Sensor) or E02 (Freezer Sensor) on the door touch panel or main LED console when the power module control board (12008381, 11012988, 12014138) detects an open or shorted NTC thermistor circuit on Temperature Sensor Probe 00628333 (supersessions 00618032, 00606327, 10008542).

The temperature sensing network consists of: Electronic Power Module → cabinet wire harness → 2-pin molex connector → 5.0 kΩ NTC thermistor probe 00628333 clipped inside the fresh food air duct or freezer evaporator wall. As compartment temperature drops, thermistor resistance increases in a precise logarithmic curve (5.0 kΩ at 77°F / 16.3 kΩ at 32°F / 32.5 kΩ at 0°F). If moisture intrusion, thermal cycling, or cabinet harness chafing causes the thermistor to read open (∞ Ω), shorted (0 Ω), or out of calibration, E01 / E02 is triggered and cooling regulation fails.

E01 / E02 with frozen fresh food items: Thermistor failed open (∞ Ω), causing the power module to run the compressor continuously. E01 / E02 with warm cabinet (>50°F) and alarm chime: Thermistor shorted (< 200 Ω) or disconnected sensor lead at main board header. Related Bosch repair guides: Bosch dishwasher E15 flood sensor guide, Bosch dishwasher E22 / E25 drain pump guide, and Bosch washer E23 AquaStop base pan flood switch guide. Local service page: Bosch appliance repair.

Safety: Disconnect 120 VAC power at the house circuit breaker or wall outlet before removing interior air duct covers or handling power module wiring headers behind the lower rear machine compartment.

Step-by-step diagnostic hierarchy

1. Locate and inspect thermistor housing (Power OFF — visual check) — Unplug refrigerator and remove food shelves/baskets:

   • Fresh Food Sensor (E01): Located behind the rear plastic air tower cover or right side wall light diffuser.
   • Freezer Sensor (E02): Located behind the lower rear freezer duct wall or near the top fan intake chute.
   • Remove 1-2 T20 Torx screws securing plastic sensor cap, pull thermistor 00628333 forward, and inspect wires for insulation corrosion or ice damage.

2. Measure NTC thermistor resistance at 2-pin plug (Power OFF — meter check) — Unclip 2-pin molex connector from thermistor lead:

   • Set multimeter to 20k Ω (20,000 Ω) scale:
     • Measure across the 2 male terminals on thermistor lead 00628333:
     • 77°F (Room Temp / 25°C): Expected 4.8 kΩ to 5.2 kΩ (5.0 kΩ nominal).
     • 32°F (Ice Water Bath / 0°C): Submerge probe tip in ice water for 3 minutes: expected 15.8 kΩ to 16.8 kΩ (16.3 kΩ nominal).
     • 0°F (Freezer Temp / -18°C): Expected 31.0 kΩ to 34.0 kΩ (32.5 kΩ nominal).
   • Result: ∞ Ω (Open circuit): Internal NTC wire is severed → replace Temperature Sensor 00628333 / 00618032. < 200 Ω (Shorted): Replace sensor assembly.

3. Verify temperature-to-resistance calibration accuracy (Power OFF — bench test) — If thermistor reads 8 kΩ at 77°F, resistance has drifted out of calibration:

   • Compare resistance reading against standard NTC curve (5.0 kΩ at 77°F).
   • Result: Resistance drifted > 10% off spec → replace Sensor 00628333.

4. Test cabinet wire harness continuity to Power Module (Power OFF — harness check) — Remove lower rear machine compartment panel and locate main power module:

   • Unclip thermistor header X4 (or X5) from power module 12008381:
     • Set meter to 200 Ω range:
     • Measure pin-to-pin between sensor 2-pin plug and header X4 terminals:
     • Expected continuity: < 0.5 Ω per wire.
   • Result: ∞ Ω: Wire fractured inside cabinet foam insulation → repair terminal connector or replace sensor harness lead.

5. Inspect and replace Power Module Board 12008381 (Power OFF — board check) — If thermistor reads 5.0 kΩ at 77°F / 16.3 kΩ at 32°F and harness continuity is < 0.5 Ω:

   • Inspect Power Module Board 12008381 / 11012988 for burned ADC input resistors near header X4.
   • Replace Power Module Assembly if analog sensor input channel is blown.

Multimeter and safety checks

Disconnect 120V AC power supply before taking resistance measurements or disconnecting main board headers.

Component / Test	Setup & Meter Range	Expected Normal Value	Fault / Failure Mode
Thermistor 00628333 (77°F / 25°C)	Across 2 thermistor pins, 20k Ω	4.8 kΩ–5.2 kΩ (5.0 kΩ)	∞ Ω (open thermistor; logs E01/E02) or < 200 Ω
Thermistor 00628333 (32°F / 0°C)	Ice water bath test, 20k Ω	15.8 kΩ–16.8 kΩ (16.3 kΩ)	Resistance fails to rise in ice water
Thermistor 00628333 (0°F / -18°C)	Cold freezer cavity, 200k Ω	31.0 kΩ–34.0 kΩ (32.5 kΩ)	Flatline resistance (causes inaccurate cooling)
Harness Wire Continuity	Pin-to-pin sensor to header X4, 200 Ω	< 0.5 Ω per line	∞ Ω (broken wire inside cabinet harness)

Root cause vs repair breakdown

Observable Symptom	Root Cause / Faulty Part	Corrective Repair Action
E01 / E02 code, thermistor reads ∞ Ω	Open NTC sensor element or wire break	Replace NTC Temperature Sensor 00628333 / 00618032
E01 code, fresh food compartment freezes food	Thermistor failed open; board runs compressor	Replace Fresh Food NTC Thermistor 00628333
E02 code, freezer thaws, thermistor reads < 200 Ω	Shorted NTC sensor element	Replace Freezer NTC Thermistor 00628333
E01 / E02 code, sensor and harness test OK	Damaged ADC sensor circuit on power module	Replace Electronic Power Module Board 12008381

FAQ

What do E01 and E02 error codes mean on a Bosch refrigerator?

E01 indicates a Fresh Food Compartment NTC Thermistor Failure, and E02 indicates a Freezer Compartment NTC Thermistor Failure. The electronic power module control board (12008381 / 11012988) detects that sensor resistance from NTC thermistor probe 00628333 (or 00618032) is out of the valid 1 kΩ to 100 kΩ operating window.

How do I test Bosch refrigerator thermistor 00628333 with a multimeter?

Unplug the refrigerator and unbolt the plastic thermistor housing cover inside the fresh food or freezer cavity. Unclip the 2-pin thermistor connector. Set multimeter to 20k Ω (20,000 Ω) scale: test across the 2 thermistor terminals. Expected room temperature (77°F / 25°C) resistance is 5.0 kΩ (5,000 Ω); in ice water (32°F / 0°C), resistance rises to 16.3 kΩ.

Why does an E01 or E02 error cause food to freeze or spoil in Bosch refrigerators?

The main power module uses thermistor feedback to modulate inverter compressor speed and air damper motor opening. If thermistor 00628333 fails open (∞ Ω), the board senses a false high temperature, driving the compressor at maximum speed and freezing fresh food. If shorted (< 100 Ω), the board senses false extreme cold and shuts off cooling.

Do I replace thermistor 00628333 or the main power module board?

If thermistor resistance is open (∞ Ω), shorted (< 200 Ω), or drifted off calibration (e.g., 2.0 kΩ at 77°F), replace NTC Thermistor Sensor 00628333 / 00618032. If thermistor measures 5.0 kΩ at 77°F / 16.3 kΩ at 32°F and cabinet wiring harness reads < 0.5 Ω to main board header X4, replace Power Module Board 12008381.

When to schedule professional service

If power module board replacement, sealed system inverter compressor diagnostics, or cabinet wiring harness repair is required, certified Bosch refrigerator technicians are available. Schedule Bosch refrigerator repair → or contact our technical department.