Bertazzoni REF36FDFZXNT Code E4: Refrigerator Frost Sensor

What E4 means

On the Bertazzoni REF36FDFZXNT French-door refrigerator with Quattro Temp Zone, E4 means the refrigerator frost sensor has failed. This sensor watches the cooling coil of the fresh-food side to judge frost build-up and defrost timing. The code appears while the controls are in locked mode, cycles with other codes if several are present, and an alarm chime sounds until a button is pressed.

Common causes of E4

A refrigerator frost sensor with an open or shorted reading
A damaged wire or plug at the coil sensor
Heavy frost covering the sensor
A control input that no longer reads the frost sensor

✓ One safe check you can try

1. Press any button to silence the chime. 2. Look at the back wall of the fresh-food section for frost or a layer of ice. 3. Keep shelves loose so air can flow behind the food. 4. Make sure both doors seal without gaps. 5. If E4 comes back after a day, call us rather than chipping ice.

! Why to stop there

Chipping or scraping frost can puncture the evaporator, which is a costly sealed-system repair.
The sensor sits behind the rear liner, which is not meant to be opened by owners.
Ignoring a frost reading can lead to restricted airflow and warm food.

Opening a panel yourself does not automatically cancel a manufacturer warranty, but it can cause accidental damage, and some manufacturers set their own service conditions. Check your warranty terms, or ask us, before deciding.

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Other Refrigerator codes

Fridge too warmBertazzoni TFT Column Message "Fridge too warm": refrigerator section above its setting Ice Maker Does Not WorkBertazzoni BMBI Refrigerator Message "Ice Maker Does Not Work": icemaker off or water not connected Lower unit openBertazzoni BMBI Refrigerator Message "Lower unit open": freezer door left open Lower unit too coldBertazzoni REF30/36BMBI Message "Lower unit too cold": Freezer Drawer Running Below Setpoint Lower unit too warmBertazzoni REF30/36BMBI Message "Lower unit too warm": Freezer Above Its Target Power Failure!!Bertazzoni Column Refrigerator Message "Power Failure!!": Long Power Interruption Recorded Refrigerator too warm / Refrigerator too coldBertazzoni REF30/36BMBI Messages "Refrigerator too warm" and "too cold": Fresh-Food Side Off Target Replace filterBertazzoni REF30/36BMBI Message "Replace filter": Water Filter Cartridge at 30 Percent

E4E4 questions

What is a frost sensor for?

It tells the control when frost has formed on the coil so the defrost can run at the right time. If it cannot read, the control may defrost too often or too rarely.

Will the refrigerator stay cold with E4?

Usually for a while. Without correct frost information, ice may slowly build up and reduce airflow, so the fresh-food side can warm up over days. Watch it with a thermometer.

What do you do on a visit?

We check the frost sensor and its wiring, look at the coil, and tell you the price before any work. The repair carries a 30-day workmanship warranty.