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Error code reference

Thermador Oven Error Code E118

Upper/single cavity (Cvt 1) cooling fan supervision error

Thermador codesThermador oven codes

Upper/single cavity (Cvt 1) cooling fan supervision error — cooling fan speed is too low or too high.

First step from the service manual

Refer to Diagram 2/4. Ensure wire harness not touching motor or pinched. Confirm plenum not touching fan end cap. Check Hall Effect Sensor connection.

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

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What E118 means on a Thermador oven

The E118 error code on a Thermador oven indicates a cooling fan supervision fault in the upper or single cavity (Converter 1). The control board continuously monitors the speed of the cooling fan using a Hall Effect Sensor, which generates pulses as the fan motor spins. When the detected fan speed falls outside the acceptable range, either too low or too high relative to the commanded speed, the board registers this fault and displays E118. The cooling fan is a critical component that protects the oven's electronic controls and cavity from thermal damage during and after cooking cycles.

The primary diagnostic starting point is to inspect the wiring harness associated with the cooling fan circuit, as referenced in Diagram 2/4. A harness that is pinched, routed too close to the motor body, or making contact with the fan end cap can cause intermittent or incorrect signals to reach the control board. Similarly, if the plenum housing is physically contacting the fan end cap, it can restrict blade rotation and artificially reduce the fan speed reading. These mechanical interference issues are among the most common root causes of this code.

The Hall Effect Sensor is the specific feedback device that communicates fan speed to the control board. A loose, corroded, or damaged connector at the sensor will disrupt the pulse signal, causing the board to interpret the fan as running at an incorrect speed. If the wiring and mechanical clearances check out, the sensor itself or the fan motor may be faulty. A failed motor that draws excessive current or spins erratically can produce speed readings outside the acceptable threshold, triggering E118.

Source: manufacturer service documentation.

Common causes of E118

  1. 01

    Pinched or misrouted wire harness

    Wiring / connection

    If the wire harness is touching the fan motor body or is pinched at any point, signal interference or a short can produce incorrect speed readings at the control board. Inspect the full harness run per Diagram 2/4 for any contact points or damage.

  2. 02

    Plenum contact with fan end cap

    Wiring / connection

    Physical contact between the plenum housing and the fan end cap restricts blade rotation, reducing fan speed below the acceptable threshold. Check for proper clearance and reposition or reseat the plenum if contact is found.

  3. 03

    Hall Effect Sensor connection fault

    Wiring / connection

    A loose, dirty, or corroded connector at the Hall Effect Sensor will interrupt the speed feedback signal sent to the control board. Disconnect, inspect, and reseat the sensor connector, looking for bent pins or corrosion.

  4. 04

    Failed Hall Effect Sensor

    Part replacement

    If the sensor connector is secure but the signal remains out of range, the Hall Effect Sensor itself may have failed internally. Replacing the sensor is required to restore accurate fan speed monitoring.

  5. 05

    Defective cooling fan motor

    Part replacement

    A worn or failing fan motor may spin erratically, too slowly, or not at all, producing a speed reading that falls outside the control board's acceptable parameters. If all wiring and sensor checks pass, the motor should be tested and replaced if faulty.

See the test procedure for each cause

Frequently asked questions about E118

What does E118 mean on a Thermador oven?
E118 indicates a cooling fan supervision error in the upper or single oven cavity. The control board has detected that the cooling fan speed is either too low or too high compared to the expected operating range. This fault is monitored through a Hall Effect Sensor that tracks fan rotation speed. The error points to a wiring issue, a mechanical obstruction, a faulty sensor, or a failing fan motor.
Can I fix E118 on my Thermador oven myself?
Some causes of E118 can be addressed without replacing parts. Checking that the wire harness is not pinched or contacting the motor, confirming the plenum is not touching the fan end cap, and reseating the Hall Effect Sensor connector are all steps a skilled DIYer can perform. If those checks do not resolve the fault, replacing the sensor or fan motor will require comfort with appliance disassembly and electrical components.
Is it safe to use my Thermador oven when E118 is displayed?
It is not recommended to continue using the oven while E118 is active. The cooling fan protects the oven's electronic control components from heat buildup during and after cooking cycles. Operating without a properly functioning cooling fan risks overheating the control board and other internal parts, which can lead to more extensive and costly damage.
Will resetting the oven clear the E118 error code?
A power reset by turning off the circuit breaker for 30 to 60 seconds may temporarily clear the code, but it will return if the underlying fault is not corrected. The control board will resume monitoring fan speed as soon as the oven is powered and operated again, and any mechanical or electrical issue causing the fault will trigger E118 again.
How much does it cost to repair a Thermador oven showing E118?
Repair costs depend on which component is at fault. If the issue is a simple wiring adjustment or connector reseat, there may be no parts cost and only a service call fee, which typically ranges from $75 to $150. Replacing the Hall Effect Sensor or fan motor will add parts costs, and total repair bills for those scenarios commonly range from $200 to $500 or more depending on labor rates in your area.

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