--- title: "U-Line error code E4" description: "U-Line error code E4: Thermistor 4 open. In plain terms, the fourth sensor, carried only by the largest multi-zone and combination units." url: "https://ulinemiami.support/error-codes/error-code-e4/" date_modified: "2026-08-30" Appliance type: "Ice machines" --- # U-Line error code E4 ### What E4 means, in the maker’s own words Thermistor 4 open. In plain terms, the fourth sensor, carried only by the largest multi-zone and combination units. A word about where this number comes from, because it changes what it is worth. U-Line prints two lists in the same manual. One is the control board’s — every number the board can log, whether or not the machine in front of you has the part. The other is that model’s own service menu, which writes ‘Does not apply to this model’ against what the unit cannot raise. This number is on the first list and on none of the second lists in the forty-four manuals we read. The meaning below is the maker’s; whether it can reach your unit depends on whether your unit has the hardware. ### Quoted rather than interpreted > E4: Thermistor 4 open. From ERROR CODES, Troubleshooting Extended, in a User Guide & Service Manual downloaded from U-Line’s own site. Nothing on this page is decoded beyond what that sentence says. ### Whether it can reach your machine at all This number is on the control board’s printed list and in no model’s own service menu among the forty-four manuals read for this site — every menu that names it says “Does not apply to this model”. That is not a gap in our research; it is the difference between what a board can log and what a machine can raise. Whether it applies to your unit depends on whether your unit has the hardware behind it, and that is a question worth asking rather than assuming in either direction. ### What to do about it - Do not clear the log before somebody has read it. The list is the evidence, and clearing it throws away the order the errors happened in. - Ask for the error log to be read. On this make the numbers live in the control’s service menu — a hidden key held for ten seconds, then option 14 on the older boards and option 21 on the current ones — and the log scrolls the errors in the order they happened. - Expect the sensor itself to be checked rather than replaced on sight. The maker’s own figure is 16.1k ohms in an ice-water bath, plus or minus five percent, and it also says a corroded connection changes the reading on its way to the board — which is why every thermistor connection leaves the factory with dielectric grease on it. - Have the model and serial numbers ready. They are on a plate on the upper right or the rear wall of the interior, and the board also has to be programmed to the right model number for its own diagnostics to mean anything. ### Where this goes next The job this usually becomes is [thermistor and sensor replacement](/services/thermistor-and-sensor-replacement/), and every one of those pages carries a starting figure and the reasons that move it. If it turns out to be nothing — and on this make a real share of these are modes rather than problems — the visit ends there and you pay the diagnostic and nothing else, or call [(305) 851-2207](tel:+13058512207) and describe what the display is doing before booking anything. Search demand for this one is close to nothing, and that fits: no model’s own menu claims it. It is here so that a reader who finds a 4 in a log knows what the board means by it. On the control board's list; no model's own service menu claims it What this one means What E4 means, in the maker’s own words Thermistor 4 open. In plain terms, the fourth sensor, carried only by the largest multi-zone and combination units. A word about where this number comes from, because it changes what it is worth. U-Line prints two lists in the same manual. One is the control board’s — every number the board can log, whether or not the machine in front of you has the part. The other is that model’s own service menu, which writes ‘Does not apply to this model’ against what the unit cannot raise. This number is on the first list and on none of the second lists in the forty-four manuals we read. The meaning below is the maker’s; whether it can reach your unit depends on whether your unit has the hardware. Quoted rather than interpreted E4: Thermistor 4 open. From ERROR CODES, Troubleshooting Extended, in a User Guide & Service Manual downloaded from U-Line’s own site. Nothing on this page is decoded beyond what that sentence says. Whether it can reach your machine at all This number is on the control board’s printed list and in no model’s own service menu among the forty-four manuals read for this site — every menu that names it says “Does not apply to this model”. That is not a gap in our research; it is the difference between what a board can log and what a machine can raise. Whether it applies to your unit depends on whether your unit has the hardware behind it, and that is a question worth asking rather than assuming in either direction. What to do about it Do not clear the log before somebody has read it. The list is the evidence, and clearing it throws away the order the errors happened in. Ask for the error log to be read. On this make the numbers live in the control’s service menu — a hidden key held for ten seconds, then option 14 on the older boards and option 21 on the current ones — and the log scrolls the errors in the order they happened. Expect the sensor itself to be checked rather than replaced on sight. The maker’s own figure is 16.1k ohms in an ice-water bath, plus or minus five percent, and it also says a corroded connection changes the reading on its way to the board — which is why every thermistor connection leaves the factory with dielectric grease on it. Have the model and serial numbers ready. They are on a plate on the upper right or the rear wall of the interior, and the board also has to be programmed to the right model number for its own diagnostics to mean anything. Where this goes next The job this usually becomes is thermistor and sensor replacement, and every one of those pages carries a starting figure and the reasons that move it. If it turns out to be nothing — and on this make a real share of these are modes rather than problems — the visit ends there and you pay the diagnostic and nothing else, or call [(305) 851-2207](tel:+13058512207) and describe what the display is doing before booking anything. Search demand for this one is close to nothing, and that fits: no model’s own menu claims it. It is here so that a reader who finds a 4 in a log knows what the board means by it. --- **[Read full article: U-Line error code E4](https://ulinemiami.support/error-codes/error-code-e4/)**