U-Line Ice Machine Code E4: Fourth Sensor Open

What E4 means

U-Line ice machines like the UONB115 and UHNP315 post E4 when Thermistor 4 reads open. The control is not receiving a signal from its fourth temperature sensor, so the circuit is broken between the sensor and the board. Clear ice models like the UCLR1215 skip E4 entirely. Ice production slows while E4 is displayed. Shorted, the same sensor shows E8.

Common causes of E4

Thermistor 4 has failed open
The sensor lead is broken or a connector is loose
The control is not reading the input

✓ One safe check you can try

1. Turn the machine off for a minute and power it back up. 2. Make sure nothing blocks airflow around the cabinet. 3. Check that the bin door is closed. 4. Leave panels in place. 5. A returning E4 is the point to call us.

! Why to stop there

A broken sensor circuit is not visible without opening the machine
Swapping parts blindly raises the bill
We diagnose first, quote in writing and give a 30-day workmanship warranty

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.

→Same appliance

Other Ice Machine codes

Ice / Off scrolling with SPU-Line Echelon 2000 Message "Ice / Off scrolling with SP": ice maker off mode CLU-Line Echelon 2000 Message "CL": self-cleaning cycle running CLR2060 one flashU-Line CLR2060 One flash: overflow protection circuit open CLR2060 two flashesU-Line CLR2060 Two flashes: open thermistor or too warm CLRCO2075 LED 2 flashingU-Line CLRCO2075 LED 2 flashing: open thermistor CLRCO2075 LED 3 flashingU-Line CLRCO2075 LED 3 flashing: drain pump blocked or overloaded E6U-Line Ice Machine Code E6 Reads Sensor 2 as Shorted E7U-Line Nugget Ice Machine Code E7: Third Sensor Shorted

E4E4 questions

What does E4 mean on my ice machine?

E4 means Thermistor 4 is open. The control has no signal from its fourth sensor, so the circuit is broken somewhere between the sensor and the board.

Why does the UCLR1215 never show E4?

The clear ice UCLR1215 uses fewer sensors, so E3, E4, E7 and E8 do not apply to it. If your clear ice machine shows a different code, tell us exactly what the display reads.

What is the shorted version of E4?

E8 reports Thermistor 4 shorted and is the counterpart to E4. Open and shorted readings come from the same sensor circuit, so we test that circuit for either code.