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Error code reference

U-Line Ice Maker Error Code E4

Thermistor 4 open

U-Line codesU-Line ice maker codes
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What the E4 error code actually means

The E4 code means your U-Line ice maker's temperature sensor has stopped sending a signal to the control board, so the machine cannot tell how cold it is inside the unit. The ice maker shuts down to protect itself because it cannot safely manage the ice making process without that information. A technician will need to test the sensor and its wiring to determine whether the sensor itself or a connection has failed.

Diagnostic procedure

The full E4 procedure

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1
First diagnostic step
Check thermistor connections and OHM test the thermistor.
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Most common causes of E4

Ranked by how often they cause this code
  1. 1Failed ice maker thermistor
  2. 2Loose or disconnected thermistor connector
  3. 3Damaged wiring harness
  4. 4Corroded or oxidized connector terminals

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Questions people ask about E4

What does E4 mean on a U-Line ice_maker?
E4 indicates that the Thermistor 4 circuit, which is the ice maker temperature sensor circuit, is open. This means the control board is not receiving any signal from the ice maker thermistor. The unit cannot operate the ice making cycle safely without a valid temperature reading, so it displays this fault and stops production.
Is it safe to continue using my U-Line ice maker when E4 is displayed?
It is not recommended to continue attempting to run the ice maker while the E4 fault is active. The unit cannot regulate its ice making cycle without a functioning thermistor, and operating it in this condition could lead to component damage. Address the fault before resuming normal use.
How much does it cost to repair a U-Line ice maker E4 error?
If only a wiring connection needs to be reseated or a terminal cleaned, repair costs may be limited to a service call fee, typically in the range of $75 to $150. If the thermistor itself needs replacement, parts costs are generally in the $20 to $60 range, with total repair costs including labor often falling between $100 and $250 depending on your location and the technician's rates.
How do I fix the E4 error on my U-Line ice maker?
Start by inspecting the thermistor wiring harness and connectors for any loose, disconnected, or visibly damaged connections. Next, use a multimeter to ohm test the thermistor directly. If the thermistor reads infinite resistance or OL, it has failed and needs to be replaced. If the thermistor tests within a normal resistance range, trace the wiring back to the control board to find the break in the circuit.
Will resetting my U-Line ice maker clear the E4 error?
A power reset may temporarily clear the displayed code, but the E4 error will return if the underlying thermistor circuit issue has not been resolved. The fault is tied to a hardware problem, not a software glitch, so the thermistor and its wiring must be tested and repaired before the error will clear permanently.

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