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Error code reference

Bosch Range Error Code E118

Cooling fan speed too low

Bosch codesBosch range codes

Cooling fan speed too low — fan speed has been sensed as too low.

First step from the service manual

Check connections to the fan and control module. Check all wires for pinched or damaged. Check fan for operation and/or blockage and/or mechanical jamming. Run Fan Test in Service mode.

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 Bosch range

The E118 error code on a Bosch range indicates that the control system has detected the cooling fan operating at a speed below the expected threshold. The cooling fan is responsible for drawing heat away from the electronic control components, particularly the control module, during and after cooking cycles. When the fan's rotational speed drops below the minimum required level, the control board interprets this as a fault condition and triggers E118 to prevent heat-related damage to sensitive electronics.

The most common causes of this fault involve the fan motor itself, the wiring harness connecting the fan to the control module, or a physical obstruction interfering with blade rotation. The control board monitors fan speed through a feedback signal, typically from a tachometer or hall-effect sensor integrated into the motor. If that signal is absent or reads below the acceptable range, the error is set. A mechanically jammed fan, a motor winding failure, or a pinched wire disrupting the feedback circuit can all produce this result.

Diagnosing E118 begins with a visual inspection of the fan wiring and connectors for damage, corrosion, or loose terminals. Technicians should also physically check the fan blade for debris, grease buildup, or mechanical binding that would restrict rotation. Bosch service mode includes a Fan Test function that commands the fan to run at full speed, allowing direct observation of fan behavior and confirmation of whether the fault is mechanical or electrical in nature.

Source: manufacturer service documentation.

Common causes of E118

  1. 01

    Fan blade obstruction or mechanical jam

    Wiring / connection

    Grease buildup, debris, or a foreign object lodged in the fan assembly can physically restrict blade rotation, causing speed to drop below the minimum threshold. Inspect the fan blade by hand for any resistance or binding when the unit is unplugged.

  2. 02

    Loose or damaged wiring connections

    Wiring / connection

    A pinched, corroded, or disconnected wire between the fan motor and the control module can interrupt power supply or the speed feedback signal, triggering the fault. Check all connectors at both the fan and the control board for secure seating and visible damage.

  3. 03

    Cooling fan motor failure

    Part replacement

    The fan motor itself may have failed due to worn bearings, a burned winding, or internal component degradation, preventing it from reaching the required operating speed. Running the Fan Test in service mode can confirm whether the motor responds to a commanded full-speed signal.

  4. 04

    Control module fault

    Part replacement

    If the control module is not sending the correct voltage to the fan motor or is misreading the speed feedback signal, it may incorrectly log E118 even when the fan is mechanically sound. This is typically diagnosed after ruling out wiring and motor issues.

See the test procedure for each cause

Frequently asked questions about E118

What does E118 mean on a Bosch range?
E118 on a Bosch range means the control system has detected that the cooling fan speed is too low. The cooling fan protects the electronic control components from heat during operation. When the fan's rotational speed falls below the expected level, the range logs this fault to prevent heat damage to the electronics. You will need to inspect the fan, its wiring, and potentially run the Fan Test in service mode to pinpoint the cause.
Can I fix the E118 error on my Bosch range myself?
Some causes of E118 are accessible to a knowledgeable DIYer. Checking for a physically blocked or jammed fan blade and inspecting wiring connectors for loose or damaged terminals can be done without special tools after unplugging the appliance. However, testing the fan motor, interpreting the Fan Test in service mode, and replacing the control module are tasks better suited to a qualified technician with experience on Bosch appliances.
Is it safe to use my Bosch range while the E118 code is active?
It is not advisable to continue using the range while E118 is active. The cooling fan exists specifically to protect the electronic control components from overheating. Operating the range without proper fan function risks permanent heat damage to the control module, which can lead to more extensive and expensive repairs. Discontinue use until the fault is diagnosed and corrected.
Will resetting the range clear the E118 error code?
A simple power reset may temporarily clear the E118 error, but the code will return if the underlying problem has not been fixed. Because the control board continuously monitors fan speed during operation, any condition that causes the fan to run too slowly will trigger the fault again. A reset is useful for confirming whether the fault is intermittent, but it is not a substitute for proper diagnosis and repair.
How much does it cost to repair a Bosch range showing E118?
Repair costs for E118 vary depending on the root cause. If the fix involves clearing a fan obstruction or reseating a connector, costs are minimal, primarily covering a service call in the range of $75 to $150. Replacing the cooling fan motor typically adds $50 to $150 in parts. If the control module requires replacement, total repair costs including parts and labor can range from $300 to $600 or more depending on the specific model.

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