--- title: "Middleby Marshall PROBE_TL_FAULT: the CTX top left zone probe reads open" description: "What PROBE_TL_FAULT means on Middleby Marshall PROBE_TL_FAULT: the CTX top left zone probe reads opens, what to check before booking, and when it is not a…" url: "https://commercialappliancerepair.center/error-codes/middleby-marshall-probe-tl-error/" --- # Middleby Marshall PROBE_TL_FAULT: the CTX top left zone probe reads open A CTX oven divides its infrared panels into zones above and below the belt, each with its own temperature probe. ## What PROBE_TL_FAULT actually means. A CTX oven divides its infrared panels into zones above and below the belt, each with its own temperature probe. The manual labels this message Probe Open: Top Left and says it appears when that zone reports more than 1400°F for over 5 seconds, a reading the control treats as a broken probe circuit. The same table has matching messages for the other three zones. Middleby Marshall commercial appliance display · also shown as PROBE_TL_FAULT, PROBE_TR_FAULT, PROBE_BL_FAULT, PROBE_BR_FAULT What to do when PROBE_TL_FAULT shows on the commercial appliance ### Kind of code Sensors 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 to Commercial controls and board repair Controllers, touch panels, relays, contactors and interlocks tested, and replaced only when the evidence says so. ### Shows up as Commercial 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. ### Make Middleby Marshall Middleby Marshall ovens on this site are the kitchen's non-pizza baking and roasting work; pizza service calls belong to our pizza oven site. ### Source Middleby Marshall CTX DZ26T, DZ33T and DZ55T infrared conveyor oven owner's operating and installation manual (Rev G) CTX DZ26T, DZ33T and DZ55T infrared conveyor ovens with the touch screen (manual Rev G). The message shows only on the Manual Mode and Preset Mode main screens. The other zones print PROBE_TR_FAULT (top right), PROBE_BL_FAULT (bottom left) and PROBE_BR_FAULT (bottom right) with the same explanation. ## Before you book, in this order. Each step comes from Middleby Marshall's own guidance for PROBE_TL_FAULT on its commercial appliances. Follow it to the end: the last card says whether this is a visit. 01 Acknowledge the message and look at the zone temperatures on the screen for one that reads far off the others. 02 Run a test item and compare how it browns on the top left side with the rest. 03 Hold product for that lane if the item comes out pale or scorched on one side. 04 Book a visit if the message comes back; the probe or its wiring behind the panels is a technician repair. ### Still there? It usually turns into [commercial controls and board repair](https://commercialappliancerepair.center/services/commercial-controls-and-board-repair/). Book with the code and the model number. ### What not to do PROBE_TL_FAULT does not mean the oven is actually at 1400°F; the number is how the control recognizes an open probe. It is also separate from the limit board messages, which watch for real overheating. ## What you may notice with it. The commercial appliance problems PROBE_TL_FAULT tends to arrive with. Answer these at the commercial appliance before anyone is booked. [All problems](https://commercialappliancerepair.center/problems/) Before you call ### [Commercial Appliance Error Code on a Combi, Fryer, Dish Machine or Laundry Display](https://commercialappliancerepair.center/problems/commercial-error-code/) [All 8 causes, cheapest first](https://commercialappliancerepair.center/problems/commercial-error-code/) It also comes with - [**Commercial Convection Oven Baking Unevenly Across the Racks**](https://commercialappliancerepair.center/problems/commercial-oven-uneven-bake/) Problem ### Commercial Appliance Error Code on a Combi, Fryer, Dish Machine or Laundry Display 8 causes, cheapest first Where PROBE_TL_FAULT 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](https://commercialappliancerepair.center/services/commercial-controls-and-board-repair/) ## Middleby Marshall commercial appliances. Middleby Marshall ovens on this site are the kitchen's non-pizza baking and roasting work; pizza service calls belong to our pizza oven site. [Middleby Marshall commercial appliance repair](https://commercialappliancerepair.center/brands/middleby-marshall/) More Middleby Marshall codes [IO_COMM_LOST](https://commercialappliancerepair.center/error-codes/middleby-marshall-io-comm-lost/) [MC1_COMM_LOST](https://commercialappliancerepair.center/error-codes/middleby-marshall-mc1-comm-lost/) [MC2_COMM_LOST](https://commercialappliancerepair.center/error-codes/middleby-marshall-mc2-comm-lost/) [FAN_HIGH_CURRENT](https://commercialappliancerepair.center/error-codes/middleby-marshall-fan-high-current/) [FAN LOW CURRENT](https://commercialappliancerepair.center/error-codes/middleby-marshall-fan-low-current/) [MC1_HIGH_CURRENT](https://commercialappliancerepair.center/error-codes/middleby-marshall-mc1-high-current/) [LIMIT BOARD HIGH TEMP](https://commercialappliancerepair.center/error-codes/middleby-marshall-limit-board-high-temp/) [LIMIT BOARD PROBE FAULT](https://commercialappliancerepair.center/error-codes/middleby-marshall-limit-board-probe-error/) [IO BOARD HIGH TEMP](https://commercialappliancerepair.center/error-codes/middleby-marshall-io-board-high-temp/) [CONTROL COMPARTMENT HIGH TEMP](https://commercialappliancerepair.center/error-codes/middleby-marshall-control-compartment-high-temp/) [HIGH TEMP CHECK FANS](https://commercialappliancerepair.center/error-codes/middleby-marshall-high-temp-check-fans/) [FAN FAULT](https://commercialappliancerepair.center/error-codes/middleby-marshall-fan-error/) [All 14 Middleby Marshall codes](https://commercialappliancerepair.center/error-codes/#codes-middleby-marshall) Sensors and probes on other makes [Alto-Shaam E20](https://commercialappliancerepair.center/error-codes/alto-shaam-e20/) [Beverage-Air E01](https://commercialappliancerepair.center/error-codes/beverage-air-e01/) [Blodgett Cavity Probe Error](https://commercialappliancerepair.center/error-codes/blodgett-cavity-probe-error/) [Continental Refrigerator E0](https://commercialappliancerepair.center/error-codes/continental-refrigerator-e0/) [Delfield E01](https://commercialappliancerepair.center/error-codes/delfield-e01/) [Dexter TEMP SENSOR SHORT](https://commercialappliancerepair.center/error-codes/dexter-temp-sensor-short/) [Frymaster E13](https://commercialappliancerepair.center/error-codes/frymaster-e13/) [Garland E21](https://commercialappliancerepair.center/error-codes/garland-e21/) [All 61 codes of this kind](https://commercialappliancerepair.center/error-codes/#family-sensor) Middleby Marshall 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 Middleby Marshall's own words > Probe Open: Top Left [Middleby Marshall CTX DZ26T, DZ33T and DZ55T infrared conveyor oven owner's operating and installation manual (Rev G)](https://www.middlebymarshall.com/wp-content/uploads/2022/01/CTX-DZ26T-DZ33T-DZ55T-Series-Electric-Oven-Rev-G.pdf) [Middleby Marshall CTX DZ26T, DZ33T and DZ55T infrared conveyor oven owner's operating and installation manual (Rev G)](https://www.middlebymarshall.com/wp-content/uploads/2022/01/CTX-DZ26T-DZ33T-DZ55T-Series-Electric-Oven-Rev-G.pdf) [Middleby Marshall CTX DZ26T, DZ33T and DZ55T infrared conveyor oven owner's operating and installation manual (Rev G)](https://www.middlebymarshall.com/wp-content/uploads/2022/01/CTX-DZ26T-DZ33T-DZ55T-Series-Electric-Oven-Rev-G.pdf) Every code on this site is taken from the manufacturer's documentation, never from a forum or a parts listing. CTX DZ26T, DZ33T and DZ55T infrared conveyor ovens with the touch screen (manual Rev G). The message shows only on the Manual Mode and Preset Mode main screens. The other zones print PROBE_TR_FAULT (top right), PROBE_BL_FAULT (bottom left) and PROBE_BR_FAULT (bottom right) with the same explanation. ## Middleby Marshall PROBE_TL_FAULT 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. 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Acknowledge the message and look at the zone temperatures on the screen for one that reads far off the others. If it comes back, it needs a visit. ### What do TL, TR, BL and BR mean in CTX probe messages? They name the zone: top left, top right, bottom left and bottom right. The letters tell the technician which probe to test before arriving. ### Is my CTX oven really at 1400°F when PROBE_TL_FAULT shows? No. An open probe circuit reads as an extreme number, and the control flags it rather than trusting it. ### Can a CTX keep cooking with one zone probe out? Three healthy zones can carry on, yet the flagged one is running without accurate control. Test a product and book a visit before relying on it. --- **[Read on the site: Middleby Marshall PROBE_TL_FAULT: the CTX top left zone probe reads open](https://commercialappliancerepair.center/error-codes/middleby-marshall-probe-tl-error/)** **[Book a visit with CommercialApplianceRepair.center](https://commercialappliancerepair.center/schedule/)**