Many Thermador Professional ranges have no display, so the oven control reports a fault by blinking two blue indicator lights in a two-digit pattern, repeated as long as the fault exists. The meanings below come from Thermador’s fault chart for its PDR and PRG Professional ranges in 30-, 36- and 48-inch widths, and from the service manuals for the all-gas Pro Grand ranges and the dual-fuel Pro Harmony PRD486, which print the same chart. A fault does not always stop the whole range: Thermador’s own example is a failed door latch, which blocks self-clean while the range keeps cooking.
How to read the blinking lights
The first blue light, labeled OVEN or OVEN ON, blinks the first digit. The second, labeled HEATING or PREHEATING, blinks the second digit. Then both pause and the sequence repeats. Four blinks followed by three is 43. Where the lights sit side by side, the left one goes first; where they are stacked, the top one does. Only the blue lights blink codes; a red CLEANING light takes no part. Codes 01 and 10 contain a zero, and Thermador’s charts do not say how a zero shows, so if only one light is blinking, note which one and the count.
Not every blink is a fault. On Pro Harmony gas ranges, the Extended Bake (Sabbath) mode blinks OVEN ON and PREHEATING slowly and together — three seconds on, three off — during the last two minutes of its 19-minute active phase. A fault code blinks one light, then the other. Newer Pro ranges with a display work differently: they store their last five control-module errors in a service mode that a technician opens.
Thermador Pro range blink codes
| Code | Fault | What the range does |
|---|---|---|
| 01 (E2) | Control not calibrated | Both ovens off on 48-inch ranges |
| 10 (E3) | Oven temperature sensor open | That oven shuts off |
| 11 (E12) | Expansion board not connected (48-inch) | Second oven disabled |
| 12 (E4) | Oven temperature sensor shorted | That oven shuts off |
| 13 (E13) | Vcc lift-off: input voltage error | Both ovens off on 48-inch ranges; shows only with the oven on |
| 21 (E5) | Potentiometer failure | That oven shuts off |
| 22 (E1) | EEPROM error (control memory) | Both ovens off on 48-inch ranges |
| 23 (E7) | Over temperature while cleaning, above 900°F | Self-clean stops |
| 32 (E6) | Over temperature while cooking, above 625°F | That oven shuts off |
| 43 (E9) | Cooling fan not operating | Self-clean stops; shows only with the oven on |
| 44 (E11) | Door latch fault | Self-clean stops; cooking continues |
| 55 (E14) | Selector switch error | That oven shuts off |
The PDR and PRG chart also gives each code an E-number, such as E9 for 43; the range shows only the blinks.
The codes to act on first
32 and 23, over-temperature. The oven passed 625°F while cooking, or 900°F while cleaning. Thermador’s checks are the temperature sensor, then the control board. Do not keep restarting that oven, and if an oven ever keeps heating with its knobs off, switch the range off at the breaker and call.
43, cooling fan not operating. Thermador’s first check is one you can help with: is the right backguard installed? The range needs a backguard designed for that model; an incompatible back accessory — backguard, low back or island trim — puts the vents in the wrong place, and the fan shuts down for lack of air. In Thermador’s bulletin photos, a dual-fuel range has two cooling fans and two vents, an all-gas range one of each. If your backguard was changed in a remodel, tell us. On Pro ranges built before September 2007, a Thermador bulletin adds another cause: the fan’s airflow (sail) switch, mounted at a downward angle, can stay closed and trigger 43 the next time the oven is used.
On Pro Harmony gas ranges, the cooling blower normally does not run at bake settings below 425°F. At 425°F and above, and in broil, it starts once the oven reaches 425°F, and after shutoff it runs until the oven cools to 375°F. If it fails to start in those conditions, Thermador says to stop using the oven and call for service.
13, input voltage error. Thermador’s first check is the neutral coming from the plug — supply wiring, a job for a technician or electrician — and then the control board.
Sensor, latch and control codes
10 and 12 — the oven temperature sensor reads open or shorted. Both start with the sensor’s connections, but the chart ends differently: a new sensor for 10, the control board for 12. See also oven not heating.
44 — door latch fault. Thermador checks the latch, the plunger switch and whether the door is aligned and closing properly. Never force a door that will not open.
21 and 55 — a potentiometer or the oven selector switch. Thermador’s checks for both include the connections and whether the part has physically come apart.
22 and 01 — an EEPROM error or an uncalibrated control; the chart’s fix is the control board. 11 — on 48-inch ranges, the expansion board is not connected; connections come first, then the board.
Older Thermador 30-inch ranges: F-codes
Thermador’s ESC30 and GSC30 30-inch ranges use F-codes. F1 — the bake or broil relay is stuck closed. Cancel clears it, but if the fault remains it returns in 16 seconds, and the fix is the relay board; treat it as urgent. F2 — cook or clean runaway temperature. F3 and F4 — the oven sensor reads open or shorted. F5 — the supervisory relay circuit is open. F6 — the control lost the 60-cycle line signal for a minute; Cancel resets it. F7 — a stuck or shorted function key, which clears only with a power-down. F8 — an analog/digital supervisory fault that cancels cooking. F9 — the door latch, which cancels self-clean. On RDF and REF 30-inch ranges, F1 is a stuck button or latch switch and F3 is the oven sensor.
What to note before you call
Watch two or three cycles and write down the count, which oven on a 48-inch range, and what it was doing — bake, broil or self-clean — plus the model number from the rating label. Thermador’s charts list no reset for these blink codes: the lights blink as long as the fault is present, and since 43 and 13 show only with the oven on, turning it off hides them without fixing anything. If nothing lights at all, Thermador’s pre-service checklist starts with power: an outage, a blown fuse or tripped breaker, or a range that has come unplugged.
One Denver note: if nothing is blinking and the complaint is baking results, altitude may be part of it. Thermador’s care manual says recipes and baking times vary at high altitudes and points bakers to Colorado State University’s Extension Service.
Why a Pro range gets tested, not guessed
One code can have very different fixes. For 43, Thermador’s chart runs from the backguard through the connections to the airflow switch or Hall effect sensor, and only then to the fan — and on ranges built before September 2007 the bulletin fix is repositioning the switch bracket, with no new part at all. A sensor that reads shorted can end at the control board, not the sensor. We read the code, test the range live, quote the actual repair, and the diagnostic fee is credited toward it.
Thermador range repair across the Denver Metro
FiXiFY repairs Thermador Professional ranges across Denver, Aurora, Lakewood, Westminster and the metro with genuine OEM parts. See range and oven repair, built-in oven repair for Thermador wall ovens, the Thermador page, or our Wolf oven error codes guide.
BOOK ONLINECALL (303) 214-1240
FAQ
How do I read the blinking lights on a Thermador range?
Count the blinks of the first blue light, labeled OVEN or OVEN ON, then the second, labeled HEATING or PREHEATING; the two counts make a two-digit code. Four blinks then three, followed by a pause, is code 43, and the pattern repeats as long as the fault exists.
What does error 43 mean on a Thermador range?
Code 43 means the cooling fan is not operating, and the clean function is stopped. Thermador’s first check is the backguard, since one with the wrong vent positions starves the fan of air; after that come the connections, the airflow switch or Hall effect sensor, and the fan itself.
Why won’t my Thermador range self-clean?
On Thermador Pro ranges, the fault chart lists three codes that stop the clean function: 23 for over-temperature during cleaning, 43 for the cooling fan and 44 for the door latch. With a latch fault alone, Thermador says the range keeps cooking; only self-clean is blocked.
Can I reset a Thermador range error code?
Thermador’s Pro range charts list no reset for the blink codes; the lights keep blinking as long as the fault exists. On older ESC30 and GSC30 ranges, Cancel clears F1, F6 and F8, though F1 comes back in 16 seconds if the fault remains, and F7 needs a power-down.
FiXiFY Appliance Repair — 7030 E 46th Ave Dr, Unit A, Denver, CO 80216 · (303) 214-1240 · support@fixifycolorado.com