Thermador Refrigerator Error Code 4-2-1

Error code 4-2-1 on a Thermador refrigerator indicates an internal ice maker fault. The refrigerator's control system has detected that the ice maker module is not functioning correctly. This fault is specific to the ice maker unit itself and is not related to external factors like water supply pressure. If the code persists after a power cycle, the ice maker module should be replaced.

Start by switching the refrigerator off and then back on to perform a power cycle. If the 4-2-1 code does not return, the issue was a temporary fault and no further action is needed. If the code comes back, the ice maker module requires replacement. Before replacing the module, also inspect the wiring harness and connector between the ice maker and the control board for any damage or loose connections.

If a power cycle clears the code, there is no parts cost involved. If the ice maker module needs to be replaced, parts costs typically range from roughly $150 to $350 depending on the specific model, with professional labor adding $100 to $200 or more depending on your region. Inspecting the wiring harness and connectors first is a no-cost step that can occasionally resolve the issue without a parts replacement.

A power cycle, turning the appliance off and back on, is the recommended first step and may clear the code if the fault was caused by a transient electronic glitch. However, if the 4-2-1 code reappears after the reset, the fault is persistent and the ice maker module will need to be replaced. A reset alone will not resolve an underlying hardware failure.

The 4-2-1 error is limited to the ice maker system and does not affect the refrigerator or freezer cooling functions. The appliance should continue to refrigerate and freeze food safely while this code is present. You can continue using the refrigerator, but the ice maker will not produce ice until the fault is resolved.