mypros+
Error code reference

Thermador Range Error Code F23

Lower oven cancel key shorted low; also keyboard gain unstable / scratches / loose molex (Sago control).

Thermador codesThermador range codes

Lower oven cancel key shorted low; also keyboard gain unstable / scratches / loose molex (Sago control).

First step from the service manual

Check all connections between control display PCB and touch panel; replace control display PCB or touch panel or both.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

MyPros+ Max

Get the full diagnostic procedure for F23.

  • Step-by-step tests with expected resistance, voltage, and continuity values
  • Wiring diagram references and connector pinouts from the OEM service manual
  • Verified part numbers when replacement is required
Get the full procedure

$29/month · Cancel anytime · Or $9.95 3-day pass

What F23 means on a Thermador range

The F23 error code on a Thermador range indicates that the lower oven cancel key has been detected in a shorted-low condition, meaning the control is reading the cancel key as continuously pressed even when it is not being activated. This error is associated with the Sago control platform and also encompasses keyboard gain instability, which can manifest as erratic key recognition, phantom key presses, or complete loss of touch panel responsiveness. The shorted condition can originate in the touch panel membrane itself, in the wiring harness connecting the touch panel to the control display PCB, or within the PCB's input circuitry.

A key contributor to this fault is physical degradation of the Molex connector between the control display PCB and the touch panel. A loose or improperly seated Molex connector can create intermittent or persistent low-resistance paths that the control interprets as a key press. Similarly, scratches or abrasions on the touch panel ribbon cable or membrane overlay can introduce unintended conductivity between circuit traces, causing the cancel key input line to register as shorted to ground.

Diagnosis begins with a thorough inspection of all connections between the control display PCB and the touch panel, paying particular attention to the Molex connector seating and the condition of the ribbon cable. If connections are secure and undamaged, the fault is isolated to either the touch panel assembly or the control display PCB itself. In many cases both components are replaced together, since keyboard gain instability can indicate deterioration in the PCB's input scanning circuitry that is not externally visible.

Source: manufacturer service documentation.

Common causes of F23

  1. 01

    Loose or unseated Molex connector

    Wiring / connection

    The Molex connector linking the touch panel to the control display PCB can work loose over time, creating a false short on the cancel key input line. Inspect the connector for proper seating and signs of corrosion or bent pins.

  2. 02

    Damaged touch panel membrane

    Part replacement

    Scratches, tears, or wear on the touch panel membrane can create unintended conductivity between circuit traces, causing the lower oven cancel key input to read as shorted low. Visually inspect the membrane and ribbon cable for any physical damage.

  3. 03

    Failed control display PCB

    Part replacement

    Keyboard gain instability on the Sago control platform can indicate deteriorating input scanning circuitry on the control display PCB. If connections and the touch panel check out as intact, the PCB itself is likely the source of the fault.

  4. 04

    Ribbon cable abrasion or damage

    Part replacement

    The ribbon cable running between the touch panel and the control board can develop shorts from rubbing against a sharp edge or chassis component. Check the cable routing and look for any visible wear or kinking.

  5. 05

    Simultaneous touch panel and PCB failure

    Part replacement

    In some cases, degradation occurs in both the touch panel and the control display PCB together, particularly in older units. When individual component testing is inconclusive, replacing both components is the recommended resolution.

See the test procedure for each cause

Frequently asked questions about F23

What does F23 mean on a Thermador range?
F23 indicates that the lower oven cancel key has been detected in a shorted-low condition on a Thermador range using the Sago control platform. The control is reading the cancel key as continuously activated even when it is not being pressed. The error can also accompany keyboard gain instability, which affects the reliability of the entire touch panel. The root cause is typically a loose Molex connector, a damaged touch panel, or a failing control display PCB.
Can I fix the F23 error code myself?
A knowledgeable DIYer can start by inspecting and reseating the Molex connector between the control display PCB and the touch panel, since a loose connection is the most common and easiest cause to address. If the connector is secure and the error persists, replacing the touch panel or the control display PCB typically requires ordering the correct part and safely accessing the control area of the range. Working inside the control panel involves exposure to line voltage components, so the unit should always be disconnected from power before any inspection or repair.
Is it safe to use my Thermador range while the F23 error is displayed?
It is not recommended to operate the range while F23 is active, as the control may not reliably accept or cancel commands due to the shorted key condition and potential keyboard gain instability. An unresponsive or erratically behaving control panel creates a risk of unintended oven operation. Disconnecting the range from power and scheduling a repair before further use is the safest course of action.
Will resetting the range clear the F23 error code?
Resetting the range by cycling power may temporarily clear the F23 error, but it will return if the underlying hardware fault is not corrected. A loose Molex connector might allow the code to clear after a reset if the connection temporarily re-establishes, but a damaged touch panel or failing PCB will cause the error to reappear. A permanent fix requires inspecting and correcting the physical cause of the shorted key condition.
How much does it cost to repair a Thermador range F23 error?
Repair costs vary depending on which components need to be replaced. A touch panel replacement or a control display PCB replacement for a Thermador range typically falls in the range of $150 to $500 or more per part, depending on the specific model. Adding professional labor costs, total repair estimates commonly range from $250 to $700 or higher. Replacing both the touch panel and control display PCB together, which is sometimes necessary, will place the repair toward the higher end of that range.

Related Thermador range codes

All Thermador range codes
View all 180 Thermador range codes

78,000+ service manuals · 160,000+ error codes · 55+ brands

Get Started

$29/month · Cancel anytime · Or $9.95 3-day pass