Bosch’s 36-inch built-in bottom-freezer refrigerators report trouble in three places: an E-code or a word such as LOWPOWER on the main display, a flashing ALARM when the freezer has run warm, and a red service light on the ice maker that blinks a three-part code. The meanings below come from Bosch’s repair instructions for this family, which also cover its Thermador, Siemens and Gaggenau versions; the Bosch models named are B36IT71SN, B36IT71SNS, B36ET71SN, B36ET71SNS, B36IT71NNP and B36IB70NSP. If your model is not on that list, the codes may not match — send us the model number from the nameplate with the code, and we will check it.
How these Bosch refrigerators report a problem
This refrigerator is two cooling systems in one cabinet: the fresh-food side and the freezer each have their own compressor, evaporator, fan and automatic defrost. They are run by a display module and by a power module in the machine compartment, with five temperature sensors feeding them — one in each compartment, one on each evaporator and one for the room. Most display codes point at one of those sensors or at the link between the two modules.
The freezer also keeps a memory. If it stays warmer than 21°F for 30 minutes, ALARM and the freezer setting flash and the buzzer beeps every second (not during a defrost or the two hours after one). Pressing ALARM OFF silences it and shows, for 10 seconds, the warmest temperature the freezer reached. Write that number down — it tells you, and us, how warm the food got.
Reading the codes yourself
Display codes appear on their own, except E06 and E07: Bosch notes that a failed evaporator sensor gives no message in normal operation and shows up only in the auto-diagnostic program. To start it, switch the refrigerator off with POWER, wait at least three minutes, switch it on, then hold ALARM OFF and SETUP together for about five seconds until LOAD 0 appears. A failed sensor brings up its code; if all pass, each component runs for five seconds. Either way the refrigerator returns to normal operation. Press only those two buttons — adding SUPER COOL opens the showroom DEMO mode instead.
Ice maker codes flash on a red LED on the ice maker, visible with the freezer open and its door switch held in. One long flash marks the start; then come three groups of one to nine flashes separated by pauses. Two flashes, then one, then one is code 2-1-1.
Display codes
| Code | What Bosch’s instructions say |
|---|---|
| E01 | Refrigerator compartment sensor open or shorted |
| E02 | Freezer compartment sensor open or shorted |
| E06 | Refrigerator evaporator sensor failed; shown only by the auto-diagnostic program |
| E07 | Freezer evaporator sensor failed; shown only by the auto-diagnostic program |
| E10 | Power module software failure |
| E11 | Display module software failure |
| E15 | Room (ambient) sensor open or shorted |
| E20 | The power module and the display module cannot communicate |
| DOOROPEN | A door has been open for more than 30 seconds |
| LOWPOWER | Supply voltage too low; the refrigerator stops working until it rises above 85 volts |
The compartment sensors are what the control uses to hold each side’s temperature. The evaporator sensors are used for automatic defrost, so a defrost problem with a blank display does not rule them out — see freezer frost buildup.
Ice maker flash codes
1-1-1, 1-2-1 and 1-3-1 — the ice cycle was interrupted; Bosch’s next step is a self test to see whether the tray still turns. 1-4-1 — the tray heater or the ice maker’s electronics. 2-1-1 and 2-2-1 — an ice maker sensor. 2-4-1 is not a failure: the self test ran with a door open.
3-1-2 and 3-2-2 — the ice maker motor. 3-1-3 and 3-2-3 — the water valve that fills the ice maker, checked before the ice maker is condemned. 3-1-4 and 3-2-4 — the tray heater. 3-1-5 and 3-2-5 — the heater on the ice maker’s water inlet. 5-1-1 and 5-2-1 — supply voltage too high or too low. The rest — 2-3-1, 3-1-1, 3-2-1, 3-3-2 to 3-3-5, 3-4-2 to 3-4-5, 4-1-1, 4-2-1 and 5-3-1 to 5-5-1 — are internal ice maker faults; for 5-3-1 to 5-5-1 Bosch checks the inlet heater at the back of the refrigerator before the ice maker.
For most of these, Bosch’s first instruction is one you can do: switch the refrigerator off and on. If the code does not return, Bosch calls it a temporary fault. If it does, the sensor, tray heater, motor and electronics inside the ice maker are not replaceable on their own, so the repair is usually a complete ice maker.
No ice and no flashing? Bosch’s troubleshooting plan starts with checks you can make: ICE showing on the display, Vacation and Sabbath off, the ice bin pushed fully back against the switch under the ice maker, the water supply on, and the filter pushed in and turned clockwise as far as it goes. Ice production also waits until the freezer is colder than about 10°F. More in ice maker not making ice.
Messages that are not a breakdown
DOOROPEN with a beep means a door has been open more than 30 seconds. Closing it ends the alarm; ALARM OFF silences it for a minute. DEMO is showroom mode: nothing that cools runs, and the sensor and low-voltage messages are hidden; switching the refrigerator off ends it. VACATION and SABBATH set the freezer to about 3°F and the refrigerator to about 45°F and turn off the interior light; Sabbath also stops the ice maker and the tones. Either word explains a warm-feeling refrigerator, and the VACATION button ends both. And ice around the freezer drawer’s gasket is often not a part at all: Bosch traces it to a gap at the bottom of the freezer door, which is an adjustment.
The ones that mean call today
E01, E02, E10, E11 and E20. The first two take away the readings the control uses to hold temperature; the rest are the control electronics themselves.
LOWPOWER that keeps returning, or ice maker code 5-2-1. The refrigerator stops working below 85 volts, so the outlet and circuit need checking along with the refrigerator.
A freezer ALARM that keeps returning, or one side warm while the other is fine. With two cooling systems, one side can fail alone. Bosch documents corroded or cracked copper tubing in the compressor area of US models leaking refrigerant and leaving one compartment with no cooling — sealed-system work for a certified technician.
No cooling and a GFCI outlet that keeps tripping. Bosch lists this complaint for these models; the component it names is the defrost heater, and improved heaters later went into production. Resetting the outlet buys time, not a fix.
Why we don’t recommend guessing parts
A 3-1-3 can be the fill valve or the ice maker. An E01 says a sensor circuit is open or shorted, not which part failed. A warm freezer can be a door gap, a defrost heater or a refrigerant leak. Bosch publishes resistance values for these sensors so they can be tested before anything is replaced, and that is how we work: we read the codes, test the component, quote the actual repair, and the diagnostic fee is credited toward it. On a 36-inch built-in, sensors, fans, heaters, valves and ice makers are all worth repairing; the replacement conversation only starts with a sealed-system failure on an older unit.
Bosch refrigerator repair across the Denver Metro
FiXiFY repairs Bosch refrigerators across Denver, Aurora, Lakewood, Westminster and the metro — same-day in most areas, genuine OEM parts. See built-in refrigerator repair, refrigerator repair, the Bosch page, or the Bosch dishwasher and Bosch washer code guides.
BOOK ONLINECALL (303) 214-1240
FAQ
What do E01 and E20 mean on a Bosch refrigerator?
On Bosch 36-inch built-in bottom-freezer models, E01 means the refrigerator compartment temperature sensor reads open or shorted, and E02 is the same fault on the freezer side. E20 means the power module and the display module have stopped communicating. Both need a technician, so write the code down before you call.
Why is my Bosch refrigerator beeping?
If DOOROPEN is on the display, a door has been open for more than 30 seconds. If ALARM and the freezer setting are flashing, the freezer has been warmer than 21 degrees F for 30 minutes; press ALARM OFF and note the warmest temperature it shows. A freezer alarm that keeps returning needs a technician.
Why is the red light on my Bosch ice maker flashing?
It is flashing a fault code. With the freezer open and its door switch held in, skip the first long flash and count the three groups that follow, for example 3-1-3 for the ice maker water valve. If switching the refrigerator off and on does not clear it, call for service.
My Bosch refrigerator says DEMO and is not cooling. What happened?
It is in showroom demonstration mode, which keeps everything that cools switched off and hides the sensor and low-voltage warnings. Switch the refrigerator off with the POWER button to end it, switch it back on, and give it time to reach temperature.
FiXiFY Appliance Repair — 7030 E 46th Ave Dr, Unit A, Denver, CO 80216 · (303) 214-1240 · support@fixifycolorado.com