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The open door of a cold stainless combi oven in a commercial kitchen, its empty racks in view and a thin core temperature probe hanging on its holder inside the cavity, nobody at the combi oven.

True E01 and E02: a Danfoss sensor reads open or shorted

True's Danfoss ERC controls watch up to four sensors, named S1 to S4, and report a failure on each as E01 to E04.

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Mon–Sat, 8am–8pm

  • Sensors and probes
  • Commercial controls and board repair
  • Source: True Residential

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What E01
actually means.

True's Danfoss ERC controls watch up to four sensors, named S1 to S4, and report a failure on each as E01 to E04. On True's Danfoss units the probes are the thermostat probe in the return air and the defrost probe on the coil. Which of them S1 and S2 are depends on how the unit is wired, so the technician reads the wiring before ordering.

True Residential commercial appliance display · also shown as E02

What to do when E01 shows on the commercial appliance

Kind of codeSensors and probes

A probe is handing the controller a reading it cannot trust, or none at all: a box or coil sensor torn loose from its clip, a fryer probe coated in carbon from oil left too long between filterings, a combi core probe with a kinked cable, or a connector gone green from steam and cleaning chemicals. The unit then runs on, stops, or shuts the heat or the cooling off to protect itself. Letting it cool and restarting it as the manual describes is fair; a probe that still reads wrong sits behind a panel, and that is a visit.

Usually leads toCommercial controls and board repair

Controllers, touch panels, relays, contactors and interlocks tested, and replaced only when the evidence says so.

Shows up asCommercial Appliance Error Code on a Combi, Fryer, Dish Machine or Laundry Display

A commercial appliance error code appears as letters or numbers on a combi, fryer, reach-in controller, dish machine or laundry machine display, or as a flashing light or an alarm tone.

MakeTrue Residential

A True cooler or prep station in a restaurant is looked at once the kitchen confirms where the held food is sitting for now.

SourceTrue Commercial Refrigeration General Control Guide, P#811072, rev. C (09/2025)

E01 to E04 are listed for the Danfoss ERC control in True's general control guide (rev. C, 2025).

Before you book,
in this order.

Each step comes from True Residential's own guidance for E01 on its commercial appliances. Follow it to the end: the last card says whether this is a visit.

01

Check the food with a separate thermometer and log the result; the display may no longer be accurate.

02

Keep the doors shut as much as possible so the cabinet holds while it waits.

03

Book a visit and mention which of E01 or E02 is showing.

Still there?

It usually turns into commercial controls and board repair. Book with the code and the model number.

What not to do

E01 is not the same as E1 on True's Danfoss ETC controls, where E1 and E2 are named sensor 1 and sensor 2 defects on a different controller. E03 and E04 point at optional sensors that many units do not carry.

What you may
notice with it.

The commercial appliance problems E01 tends to arrive with. Answer these at the commercial appliance before anyone is booked.

All problems

Before you call

Commercial Appliance Error Code on a Combi, Fryer, Dish Machine or Laundry Display

All 8 causes, cheapest first

It also comes with

Close view of the dark touch control panel on the front of a stainless combi oven in a commercial kitchen, one abstract amber warning indicator glowing among unlit icons, the steam-fogged glass door blurred beside it. Problem

Commercial Appliance Error Code on a Combi, Fryer, Dish Machine or Laundry Display

8 causes, cheapest first

Where E01 usually leads

Commercial controls and board repair.

Controller, touch panel, probe or sensor, relay, contactor, power supply, door switch or interlock, tested before anything is changed · moderate.
Book a visit What the job involves

True Residential
commercial appliances.

A True cooler or prep station in a restaurant is looked at once the kitchen confirms where the held food is sitting for now.

True Residential commercial appliance repair

More True Residential codes

HILOdOrdEFHAP1P2ConLEAuLiEoCEE
All 14 True Residential codes

Sensors and probes on other makes

Alto-Shaam E20Beverage-Air E01Blodgett Cavity Probe ErrorContinental Refrigerator E0Delfield E01Dexter TEMP SENSOR SHORTFrymaster E13Garland E21
All 60 codes of this kind
A row of three stainless steel reach-in cabinets with solid doors along the wall of a working restaurant kitchen, the reach-ins clearly the subject, one door open showing sheet pans of prepped vegetables on wire shelves, a walk-in cooler door with a clear strip curtain visible at the far end, a cook seen only from behind in a white jacket passing in the soft background, bright even kitchen light. True Residential builds this

Commercial cold storage

Reach-in and pass-through cabinets, walk-in coolers and walk-in freezers, prep and sandwich tables, undercounter units and blast chillers that hold a kitchen's food at safe temperatures.

 A working restaurant cooking line under a stainless ventilation hood, two stainless gas fryers with baskets hanging above the oil, a flat griddle and a combi oven with a glass door beside them, the equipment clearly the subject, a cook seen only from behind and shoulders down at the far end of the line, warm kitchen light, small blue flames visible under the griddle. True Residential builds this

Commercial cooking equipment

Fryers, griddles, charbroilers, restaurant ranges, convection and combi ovens, steamers, kettles, holding cabinets and toasters, on gas or electric, that make up the hot side of a kitchen line.

In True Residential's own words

E01 S1 sensor failure
True Commercial Refrigeration General Control Guide, P#811072, rev. C (09/2025) True Commercial Refrigeration General Control Guide, P#811072, rev. C (09/2025)

Every code on this site is taken from the manufacturer's documentation, never from a forum or a parts listing. E01 to E04 are listed for the Danfoss ERC control in True's general control guide (rev. C, 2025).

True Residential E01 commercial appliance repair,
where we come out.

The same visit in every metro below: the code, the model number, and a diagnosis before any part is ordered.

All service areas

Tampa BayFL · 31 areas

OrlandoFL · 30 areas

Miami / South FloridaFL · 47 areas

New York MetroNY · 75 areas

HoustonTX · 36 areas

ChicagoIL · 50 areas

Los AngelesCA · 95 areas

San DiegoCA · 31 areas

San Francisco Bay AreaCA · 74 areas

A restaurant team working a busy commercial kitchen line.
For the heart of your home.

Questions
about E01.

Can I clear E01 myself?
Check the food with a separate thermometer and log the result; the display may no longer be accurate. If it comes back, it needs a visit.
What does E02 mean on my True?
Sensor S2 on the Danfoss ERC control has failed or lost its connection. The cabinet may still run, but a technician should test the probe soon.
Can a loose plug cause E01 on a True?
Yes. A probe plug pulled half out during cleaning or a pinched wire gives the same code as a dead probe, which is why the connection is checked first.
Why does my True say E1 and not E01?
E1 comes from the Danfoss ETC control, a different model. The meaning is similar, but the probe layout differs, so tell the technician exactly what the screen shows.

Back to your everyday

Still showing E01?

A booking with a code goes further when it has the code as shown, the model and serial from the data plate, and a word on whether the unit still holds temperature, heats, rinses or spins. With those three, the office can match the likely part to your unit the same day.

Schedule a repair Call (844) 571-4566
(844) 571-4566 Schedule a repair