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Error code reference

Thermador Range Error Code 43

Fault code indicated by first LED blinking 4 times followed by second LED blinking 3 times (specific meaning…

Thermador codesThermador range codes

Fault code indicated by first LED blinking 4 times followed by second LED blinking 3 times (specific meaning not detailed in manual beyond chart reference).

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What 43 means on a Thermador range

Error code 43 on a Thermador range is communicated through the appliance's LED indicator system rather than a digital display. The code is signaled by the first LED blinking 4 times, followed by the second LED blinking 3 times. This blink-pattern communication method is typical of Thermador's legacy and mid-generation range control systems, where a dedicated display is absent or secondary to an LED diagnostic interface. The specific fault tied to this pattern is categorized within the control board's internal fault chart, though the precise subsystem it targets is not fully described in available documentation.

Because fault code 43 falls within a range of codes that Thermador control boards use to flag communication or operational errors between major components, the most probable areas of concern are the main control board, wiring harnesses, or a peripheral component that reports status back to the control board. In many Thermador range platforms using LED-based diagnostics, codes in the 40s grouping are associated with electronic control or sensor-related issues. Without a more granular description in the fault chart, technicians should approach this code by systematically inspecting the control board for visible damage, checking all wiring connections for corrosion or looseness, and testing any sensors connected to the control circuit.

Source: manufacturer service documentation.

Common causes of 43

  1. 01

    Main Control Board Fault

    Part replacement

    The control board may have developed an internal failure or communication error, causing it to log fault code 43. Inspect the board for burned components, corrosion, or damaged solder joints.

  2. 02

    Loose or Damaged Wiring Harness

    Wiring / connection

    A wiring harness connector that has worked loose or suffered heat damage can interrupt communication between the control board and connected components. Visually inspect all harness connections for damage, melting, or poor seating.

  3. 03

    Faulty Sensor or Sensor Circuit

    Part replacement

    Thermador ranges use sensors to monitor temperature and operational status, and a failed sensor or broken sensor lead can trigger a fault code. Check sensor wiring continuity and connection points at the control board.

  4. 04

    Power Supply Interruption

    Wiring / connection

    An inconsistent or insufficient power supply to the control board can cause it to log error codes during operation. Verify the range is receiving correct voltage at the terminal block and that the circuit breaker is functioning properly.

  5. 05

    Software or Memory Error on Control Board

    Wiring / connection

    The control board's onboard memory can occasionally register a false or corrupt fault code following a power surge or fluctuation. A hard reset by disconnecting power may clear the code if no underlying hardware fault is present.

See the test procedure for each cause

Frequently asked questions about 43

What does 43 mean on a Thermador range?
Error code 43 on a Thermador range is displayed through the LED indicator system as four blinks on the first LED followed by three blinks on the second LED. It indicates a fault condition logged by the control board, though the specific subsystem involved is not fully detailed in the fault chart. Technicians should inspect the control board, wiring connections, and any sensors tied to the control circuit to identify the root cause.
Can I fix error code 43 on my Thermador range myself?
Some potential causes of code 43, such as a loose wiring harness connection or a power-related glitch, can be checked by a knowledgeable DIYer comfortable working around appliance electronics. However, if the fault points to a failed control board or a damaged sensor circuit, those repairs typically require component replacement and a working knowledge of appliance wiring. If you are not comfortable inspecting internal components, a qualified appliance technician is the safer choice.
Is it safe to use my Thermador range while error code 43 is active?
It is generally not recommended to continue using the range while an undiagnosed fault code is active. The code indicates the control board has detected an abnormal condition, and operating the appliance without identifying the cause could worsen the fault or create a safety hazard. Discontinue use until the issue is diagnosed and resolved.
How much does it cost to repair error code 43 on a Thermador range?
Repair costs vary depending on the root cause. If the fix involves reseating a wiring connection, costs may be limited to a service call fee, typically in the range of $75 to $150. If the control board requires replacement, parts and labor combined can range from $300 to $600 or more depending on the specific model and local labor rates.
Will resetting my Thermador range clear error code 43?
Disconnecting the range from power for several minutes and restoring power may clear the code if it was triggered by a temporary power fluctuation or a minor software error. However, if an underlying hardware problem such as a faulty sensor or damaged control board is present, the code will likely return after the reset. A reset should be considered a first diagnostic step, not a permanent fix.

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