Bosch Dryer Error Code E:109

E:109 indicates a general error in the COM module, which is the HomeConnect Wi-Fi and smart communication module in the dryer. The fault signals that communication between the COM module and the Operating Unit has failed or is disrupted. The dryer's core drying functions may still operate, but smart connectivity features will be affected. Diagnosis starts with inspecting the wire harness between these two components.

A power reset may temporarily clear the E:109 code, but if the underlying issue such as a loose harness, damaged wiring, or failed COM module is still present, the error will return. Resetting is a reasonable first step, but a physical inspection of the COM module wiring is necessary to achieve a lasting repair.

Repair costs vary depending on the root cause. If the fix involves only reseating a connector or cleaning terminals, the cost may be limited to a diagnostic service call, typically in the range of $75 to $150. If the COM module itself requires replacement, parts and labor combined can range from $150 to $350 or more depending on parts availability and local labor rates.

Begin by unplugging the dryer and locating the wire harness that runs between the COM module and the Operating Unit. Check that all connectors are fully seated, and inspect the wiring for any visible damage or corrosion. If the harness appears intact, the COM module itself may need to be replaced. A qualified appliance technician can confirm which component is at fault through further testing.

E:109 is specifically related to the HomeConnect communication module and does not necessarily indicate a problem with the dryer's heating or mechanical systems. In many cases, the dryer can still be used for normal drying cycles while the COM module fault is present. However, it is best to have the error diagnosed promptly, as unaddressed wiring issues could develop further over time.