Thermador built-in ovens from the late 1990s and 2000s use three different fault lists, and the same letters can mean different things on each. The C, CM and CJ ovens show two-digit F-codes from F10 to F84. The CT and CMT ovens, with a Dreefs control and a selector knob, show E1 to E15 in the oven window. The S, SM and SMW ovens show short codes: F1 to F9, FC, FF, F- and Fr. The meanings below come from Thermador’s error-code charts for those families (updated February 2002), the CM301 and CM302 service manual and the SMW272 service manual. Thermador’s Professional ranges blink their codes on two lights instead; see our Thermador range error codes guide.
Which Thermador oven do you have?
| Family | How to tell | Codes look like |
|---|---|---|
| C, CM, CJ | Touch-panel built-ins such as the CM301 and CM302, which pair an oven with a microwave; the data plate is behind the right side of the cooling vent | F10 to F84 |
| CT, CMT | Ovens with a selector knob and an Oven/Selector window; Thermador’s chart assumes a paired microwave | E1 to E15 |
| S, SM, SMW | Single or double ovens with a display head; the SMW272 stacks a microwave, a warming drawer and a lower oven in one cabinet | F1 to F9, FC, FF, F-, Fr |
C, CM and CJ ovens: F10 to F84
The tens digit tells you where to look: F1x is the power/relay board, F2x the touch panel, F3x the upper oven’s sensor and cooling fan, F4x its meat probe, F5x its door and latch, and F6x, F70 and F8x repeat the pattern for the lower oven.
| Code | Meaning | What we check, and when to call |
|---|---|---|
| F10, F11, F12, F13, F14, F19 | Power/relay board: incompatibility, communication error, Vcc lift-off, not calibrated, display EEPROM error, other board error | Board connections, a jammed air switch for F13, then the board. Call: cooking is cancelled until it is fixed |
| F20, F21, F22, F23 | Upper or lower oven Cancel key reading shorted | Touch-panel connections, then the display board or touch panel. Call if it returns after a reset |
| F24, F25 | One or several touch keys stuck | Objects against the touch pads, the harnesses, then the display board and touch panel. One reset first |
| F30, F31 (F60, F61 lower) | Oven temperature sensor shorted or open | The sensor and its wiring at the board, then the power/relay board. Call: that oven cannot hold temperature |
| F32, F33 (F62, F63 lower) | Over temperature while cleaning or while cooking | Whether power was restored to an oven still above 550°F, then the sensor and the board. Call if it repeats; do not keep restarting |
| F34 (F64 lower) | Cooling fan air switch not detected | The air switch, the cooling fan and the switch wiring. Call: the oven is protecting its electronics |
| F40 (F70 lower) | Meat probe shorted | Probe wiring pinched to the chassis, then the display board. Low urgency; cook without the probe |
| F50 to F54 (F80 to F84 lower) | Door and latch: signal shorted low, stuck unlocked, locked and open at once, stuck locked, latch input shorted | The door and latch switches and their wiring, then the power/relay board, then the display board. Call: never force a locked door |
Over-temperature codes have an innocent cause worth knowing. Thermador’s first listed cause for F33 and F63 is power restored to an oven still above 550°F, for example after a breaker trip during self-clean; the fix is to let it cool below 550°F first. If the code comes back on a cool oven, it is the sensor or the power/relay board, and the oven should not be used until it is tested.
F34 is the cooling fan circuit. The control expects an air switch to close when the fan moves air; Thermador lists the switch, the fan and the switch wiring. On CM ovens a second air switch on the microwave transformer’s fan is wired in series with the one under the lower oven, so either failing to close produces F34.
Touch-panel codes often start as a connection. The touch panel is scanned constantly; if a poor harness connection interrupts the scan, the microprocessor turns all of the keys on electronically and the control reports stuck keys. Thermador’s advice is to turn off power, check the harnesses and restore power, which usually clears it; the harness check is ours, one reset at the breaker is yours.
CT and CMT ovens: E1 to E15 in the selector window
Thermador’s chart explains how to clear some of these codes: turn the selector knob to OFF, then “tweak” it slightly counterclockwise, which may stop the flashing and beeping. E1, E9, E11, E12 and E13 also need the power switched off momentarily. If a code stays in the display with the selector OFF after both steps, turn off the power and have the oven diagnosed. A paired microwave keeps working through most of these faults.
E2 is a cook or clean runaway: Thermador’s two charts put the limit at 625 to 635°F while cooking, or about 890°F in self-clean. It shuts off the heat and the microwave and clears only once the oven has cooled below the runaway temperature with the selector off; the check is the sensor, then the control board. E3 and E4 are an open or shorted sensor; heat is turned off in the failed oven only. E7 is an illegal temperature display, cleared with a mode change, and E6 points to the selector switch. E1, E5, E8, E10 and E15 are control-board faults; E1 and E5 still allow cooking, while E8, E10 and E15 leave the oven unusable until the board is replaced. E9, E11, E12 and E14 are latch-switch problems that block self-clean. E13 differs by model: on a CT the latch is frozen or has no power to its motor, and if both switches report a locked door, E13 and LOCK stay in the display in every mode; on a CMT it means the control board was never converted.
S, SM and SMW ovens: F1 to Fr
| Code | Meaning | What we check, and when to call |
|---|---|---|
| F1 | Element supervisor enabled | The main power/relay board. Call |
| F1 with F7 | Poor connection between the display head and the touch panel | The control head and the main board; see below. Call if it repeats |
| F2 | Over temperature detected, or the door light coming on an hour into self-clean | The latch switches and door light, then the sensor and board. Call; do not restart self-clean |
| F3, F4 | Open sensor; shorted sensor, or a sensor reading below 40°F | The sensor at the board and its wiring. Call if the kitchen is not freezing |
| F5 | Element supervisor disabled, single or upper oven | The sensor and wiring, a mis-plugged display harness, then the board. Call |
| F7 | Control reading a shorted key | The control head and touch panel. One power reset first, then call |
| F8 | Shorted meat probe on an oven that has no probe | The main power/relay board. Call |
| F9, Fr | Invalid door lock switch status, upper or lower oven | The latch and its switches. Call; do not force the door |
| FC, F- | Communication error seen by the display head or by the main board | Power and communication connections to the second relay board and control head, then the boards. Call |
| FF | Bad analog-to-digital converter | The sensor first, then the main board. Call |
F1 together with F7 comes from a single loss of communication between the control head and the touch panel. Thermador’s note blames heat migrating into the control-head connector, and says the updated main power/relay board keeps the cooling fan running until the oven is down to 300°F. Fr on a double oven has three meanings: an invalid latch switch status in the lower oven, a communication error at the display head, or the lower oven’s element supervisor disabled, which points at the lower sensor or lower relay board. Only a live test tells them apart.
F4 has a Colorado footnote: Thermador lists a sensor reading below 40°F as a cause, alongside a genuine short. A wall oven in a mountain cabin left unheated through a cold snap can show F4 on its first use; let it warm to room temperature and try again before you book. F4 in a warm kitchen means the sensor or its wiring needs testing.
What to do before you call
Write down the exact code, which oven on a double unit, and what it was doing. On C, CM and CJ ovens, Cancel returns the display to the clock, but a real fault comes straight back. One reset at the breaker is reasonable for a key or communication code; repeated resets of an over-temperature or door code are not. If the door is locked, leave it locked. If the oven keeps heating with everything off, switch it off at the breaker and call.
Why a wall oven gets tested, not guessed
Most of these codes name a chain, not a part. On S ovens, F2 can be the latch switches, the door light, the sensor or the board, and a sensor that reads correctly can still cause errors through a grounded lead or crushed connector contacts. We read the code, test the oven live, quote the actual repair with genuine OEM parts, and the diagnostic fee is credited toward it.
Thermador wall oven repair across the Denver Metro
FiXiFY repairs Thermador built-in ovens across Denver, Aurora, Lakewood, Westminster and the rest of the metro. See built-in oven repair, the Thermador page, our oven not heating guide, or the repair guides hub for other brands.
BOOK ONLINECALL (303) 214-1240
FAQ
What does F34 mean on a Thermador wall oven?
F34 means the control did not detect the upper oven’s cooling fan air switch closing; F64 is the same fault for the lower oven. Thermador lists the air switch, the cooling fan and an open circuit in the switch wiring, and on CM ovens a second air switch on the microwave transformer fan is wired in series with it, so either one can trigger the code.
How do I clear an error code on a Thermador built-in oven?
On C, CM and CJ ovens, any Cancel key returns the display to the clock, but the fault returns if it is still present. On CT and CMT ovens, turn the selector to OFF and tweak it slightly counterclockwise; E1, E9, E11, E12 and E13 also need the power switched off briefly. For an over-temperature code after a breaker trip, let the oven cool below 550 degrees F before restoring power.
Why does my Thermador CT oven show E13 and LOCK?
On a CT oven, E13 means the latch is frozen or there is no power to the latch motor. If both latch switches report a locked door, Thermador’s chart says E13 and LOCK stay in the display in every mode until the latch is repaired; only if the switches show an open door can the code be tweaked away. On a CMT oven, E13 means the control board was not converted.
What do Fr and FC mean on a Thermador double oven?
Fr on an S, SM or SMW double oven can mean three things: an invalid latch switch status in the lower oven, a communication error at the display head, or the lower oven’s element supervisor disabled, which points at the lower sensor or lower relay board. FC is a communication error detected by the display head, usually because the second power/relay board is not powered up.
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