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Error code reference

Gaggenau Oven Error Code E122

Core temperature sensor too high (>99°C / 212°F, resistance <1 kohm)

Gaggenau codesGaggenau oven codes

Core temperature sensor too high (>99°C / 212°F, resistance <1 kohm) – sensor short-circuit cooking compartment 1 (up to software 1.20 not displayed).

First step from the service manual

Check temperature sensor with service test programme. Check resistance value (25°C/77°F ≈ 50 kohm, 70°C/158°F ≈ 8.77 kohm). Replace KTF temperature sensor.

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

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What E122 means on a Gaggenau oven

Error code E122 on a Gaggenau oven indicates that the core temperature sensor in cooking compartment 1 has reported a reading above 99°C (212°F), which corresponds to a resistance value falling below 1 kilohm. This is the threshold the control board uses to identify a short-circuit condition in the KTF (core temperature/food probe) sensor circuit. The sensor is a negative temperature coefficient (NTC) type, meaning its resistance decreases as temperature rises. When resistance drops below the 1 kilohm threshold, the board interprets this as an implausibly high or out-of-range temperature and flags the fault. Note that on units running software version 1.20 or earlier, this code is not displayed on screen, though the fault condition may still affect oven operation.

The KTF temperature sensor has known reference resistance values that allow technicians to verify its condition: at 25°C (77°F) the resistance should measure approximately 50 kilohms, and at 70°C (158°F) it should measure approximately 8.77 kilohms. A reading well below these values, especially one approaching or below 1 kilohm at room temperature, confirms a short-circuit in the sensor itself or in its wiring harness. The diagnostic process should begin with the built-in service test programme, which exercises the sensor circuit and logs live resistance data for comparison against these reference points.

Common root causes include a damaged sensor probe, a pinched or abraded wiring harness causing a short to ground, corrosion at the sensor connector, or physical damage to the probe tip from contact with cookware. Because this sensor monitors the internal temperature of food when a probe is inserted, damage from mishandling is relatively common. If wiring and connectors check out within specification, the KTF sensor itself should be replaced.

Source: manufacturer service documentation.

Common causes of E122

  1. 01

    Failed KTF temperature sensor (internal short)

    Part replacement

    The sensor element itself has developed an internal short circuit, causing resistance to drop below 1 kilohm. Measuring resistance at the sensor connector at room temperature and comparing against the 50 kilohm reference value will confirm this failure.

  2. 02

    Damaged or pinched wiring harness

    Wiring / connection

    The wiring connecting the KTF sensor to the control board may be pinched, abraded, or melted, causing two conductors to contact each other and create a short circuit. Inspect the full harness run for visible damage, especially near oven cavity edges and mounting points.

  3. 03

    Corroded or contaminated sensor connector

    Wiring / connection

    Moisture, grease, or food residue at the sensor connector pins can create a low-resistance path that mimics a sensor short. Cleaning and inspecting the connector for corrosion or contamination may resolve the fault without replacing the sensor.

  4. 04

    Physically damaged probe tip

    Part replacement

    The food probe tip can sustain mechanical damage from contact with oven racks or cookware, which can break the internal sensor element and cause a short. Inspect the probe tip for bending, cracking, or deformation.

  5. 05

    Control board fault (misreading sensor circuit)

    Part replacement

    In rare cases, the control board itself may incorrectly interpret a normal sensor resistance as a short-circuit condition. This should only be considered after the sensor and wiring have been confirmed to be within specification.

See the test procedure for each cause

Frequently asked questions about E122

What does E122 mean on a Gaggenau oven?
E122 indicates that the core temperature sensor in cooking compartment 1 has reported a resistance below 1 kilohm, which the control board identifies as a short-circuit condition. This sensor is the KTF food probe sensor, and at normal room temperature it should read approximately 50 kilohms. A reading far below that threshold points to a fault in the sensor itself, its wiring, or its connector. On units with software version 1.20 or earlier, this error may not appear on the display even when the fault is active.
Can I fix E122 myself on a Gaggenau oven?
A knowledgeable DIYer can perform initial diagnostics by visually inspecting the sensor probe, its wiring harness, and the connector for obvious damage or corrosion. Resistance testing with a multimeter against the known reference values (approximately 50 kilohms at 25°C and 8.77 kilohms at 70°C) can confirm whether the sensor has failed. If the sensor is confirmed faulty, replacing the KTF temperature sensor is the recommended repair. For accessing the service test programme and diagnosing deeper wiring or board issues, a qualified technician is advisable.
Is it safe to use my Gaggenau oven while E122 is displayed?
It is not recommended to continue using the oven while E122 is active. A short-circuited temperature sensor means the control system cannot reliably monitor cooking compartment temperature through that circuit. This could affect oven performance, automatic cooking programmes, or safety-related temperature monitoring. The fault should be diagnosed and resolved before returning the oven to regular use.
Will resetting the oven clear the E122 error?
A power reset may temporarily clear the displayed error, but it will not resolve the underlying cause. If the KTF sensor or its wiring has an actual short circuit, the fault condition will return as soon as the oven runs a temperature check cycle. A proper repair, whether cleaning the connector, repairing damaged wiring, or replacing the sensor, is required to permanently resolve E122.
How much does it cost to repair a Gaggenau oven E122 error?
Repair costs vary depending on the root cause. If the fix is as simple as cleaning a corroded connector, costs may be limited to a service call fee, which typically ranges from roughly $100 to $200 depending on your location. Replacing the KTF temperature sensor itself generally adds parts costs on top of labor, and total repair bills for sensor replacement on a Gaggenau unit commonly fall in the range of $200 to $500 or more. Control board replacement, if required, would push costs higher.

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