Thermador Range Error Code d:18

The d:18 code on a Thermador range indicates that the WFMC motor control module has detected a peak voltage level that is too high. This is an internal motor control fault designed to protect the motor and drive electronics from overvoltage damage. The error points directly to the motor control module as the likely faulty component.

It is not recommended to continue operating the range while this fault is active. The d:18 code indicates a motor control overvoltage condition, and continuing to run the appliance could cause further damage to the motor control board or connected components. Stop using the range and have it inspected before resuming normal operation.

Repair costs will vary depending on the specific motor control module part cost and local labor rates, but motor control board replacements on Thermador ranges typically range from around $200 to $600 or more, including parts and labor. If the incoming line voltage is the cause, no parts may be required and cost would be limited to a service call. Getting a diagnostic visit from a certified technician will provide a more accurate estimate for your specific unit.

Some basic checks, such as verifying that incoming line voltage is within the normal range, can be performed by a knowledgeable DIYer with a multimeter. However, if the motor control module itself is faulty, replacement involves working with high-voltage components and internal circuitry, which is best handled by a qualified appliance technician. Attempting motor control board replacement without proper training carries a real safety risk.

A power cycle reset, such as disconnecting the range from power for several minutes and then restoring it, may temporarily clear the display, but the fault will return if the underlying cause has not been addressed. Because d:18 identifies a hardware-level fault in the motor control module, the error is unlikely to resolve permanently without repairing or replacing the faulty component.