Stero SD3 dishwasher Error Codes
Applies to: SD3 door-type dish machines. Compiled and paraphrased from the Stero SD3 Service and Parts Manual, form F45576, published by Stero, a division of Illinois Tool Works. Temperatures, timings and resistance figures are Stero's published values for the SD3. Other Stero families, the SU and SG undercounters and the SCT and ER conveyors, use different displays; confirm against the manual for your machine. Table last updated Aug 13, 2026.
How to read the codes
Stero calls these dish machines and most operators call them dishwashers; the codes are the same either way. Stero's SD3 control shows two families of code. E-codes are machine faults and appear on the main display; P-codes are thermistor faults. Both are cleared by cycling power at the machine switch, which clears the DISPLAY but not the cause. The control also stores the most recent fault in service diagnostics as a two-digit left/right pair, so a technician can see what happened before you reset it. One row of the manufacturer's chart did not extract cleanly from the manual and is deliberately omitted rather than guessed at.
The codes
| Code | Meaning | Likely causes | Operator-safe steps | Technician work |
|---|---|---|---|---|
| E2 | Water did not reach the float during fill within 150 seconds | Drain lever open or standpipe not seated, debris fouling the float, water supply off, or pressure below spec | Check the drain lever is closed and the standpipe properly seated with its O-ring clear of soil, then check the water is on. This is the one E-code an operator often fixes without a call | Verify flowing pressure at 20 psi plus or minus 5, float switch continuity at J2, and fill solenoid 1SOL operation |
| Ed | Slow leak: the machine refilled three times within 35 minutes of the initial fill | Drain not sealing, standpipe O-ring damaged or dirty, or a leak in the tank or piping | Pull the standpipe and check the O-ring for food debris or damage. Reseat it properly | Leak trace, drain valve seat, and float circuit verification |
| EE | The booster did not reach temperature within eight minutes of the initial fill | Booster power off, incoming water below the 110F minimum, failed element or contactor, tripped high limit, or scale on the elements | Check that booster power is on and the building hot water is actually hot. Cold incoming water is the common cause and is not a machine fault | Element resistance and current against the chart, contactor 3CON, high limits 2TAS and 3TAS, and booster thermistor 3QTM |
| E6 | The float and temperature thermistors could not be detected at all | The J2 connector on the control board is unplugged or a harness has failed | Nothing at operator level; the machine cannot sense water or temperature | Verify the thermistor and door switch plug is seated at J2, then test each thermistor |
| EF | Severe internal control error | Control board malfunction | Cycle power once. If it returns, the board needs attention | Control board replacement, and it must be reprogrammed as an SD3 or the machine will not work correctly |
| P1 | Wash tank thermistor open or shorted | Failed thermistor or damaged wiring | Expect no tank heat or wrong wash temperature. Do not keep running: a wash below temperature is a food safety issue, not just a cleaning one | Measure at J2-1/J2-6. Stero's chart gives 55.7k ohms at 100F, 22.6k at 140F, 15.5k at 158F and 10.1k at 180F |
| P2 | Rinse thermistor open or shorted | Failed thermistor or damaged wiring | The final rinse temperature reading cannot be trusted, which matters for your sanitising record | Measure at J2-2/J2-7 against the same resistance chart |
| P3 | Booster thermistor open or shorted | Failed thermistor or damaged wiring | Expect the booster to misbehave and the 180F final rinse to be unreliable | Measure at J2-3/J2-8 against the same resistance chart |
| Stored fault, right digit d, E, F, 2 or 6 | The control keeps the most recent machine fault in service diagnostics even after a power cycle clears the display | d is slow leak, E is booster setpoint timeout at 480 seconds, F is a control board EPROM error, 2 is water not reaching the float on initial fill, 6 is float or thermistors open | Worth mentioning to the technician that you reset the machine, and roughly when | Enter service diagnostics by holding PROG and SELECT then pressing ON. A dash in either digit means no fault recorded for that side |
| Stored fault, left digit 1, 2 or 3 | The control's record of which thermistor faulted | 1 is the wash thermistor, 2 the rinse thermistor, 3 the booster thermistor | No operator action | Read alongside the right digit; both are shown together, so 22 means rinse thermistor error and water not to float have both occurred |
If this needs a dish machine technician
24 companies in this directory name Stero on their own site: that page shows who has been phone-confirmed, who publishes 24/7 cover, and what each puts in writing. Start there if the brand matters more than the city.
Two questions worth reading before you ring anyone: what to do first when a code appears and how to tell whether it is yours to fix.
Or browse dish machines service companies by state:
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Related: the PM checklist that prevents the most common codes outright, and the operator guides for symptom-first diagnosis.
Not sure this is the right make? The lookup by code shows every make that uses a given code, and flags the ones that mean different things depending on the machine in front of you.