Samsung Air Conditioner Error Code E604

E604 indicates a setting option error for the wired remote controller on the COM2 communication port. The indoor unit has detected that the configuration transmitted by the wired remote does not match the expected system settings. This is typically caused by incorrect DIP switch positions on the remote controller. It is a configuration fault rather than a hardware failure in most cases.

A simple power reset will not permanently clear E604 if the underlying DIP switch configuration is still incorrect, because the error will return as soon as the wired remote controller attempts to communicate over COM2 again. The fault will only clear reliably after the DIP switch settings are corrected to match the system requirements. Once the configuration is fixed, a power cycle is typically needed to complete the reset.

If the issue is simply an incorrect DIP switch setting, the repair may only involve a service call fee, which typically ranges from $75 to $150 depending on the technician and region. If the wired remote controller itself is found to be defective and needs replacement, parts and labor combined can range from $150 to $400 or more depending on the specific controller model and local labor rates. In many cases no parts are required at all.

Start by locating the DIP switch bank on the wired remote controller, usually accessible by removing the controller cover. Compare each switch position to the correct configuration specified for your system model, which is often printed on a label inside the controller or in the installation documentation. Correct any switch positions that are wrong, then power cycle the system to allow the COM2 communication to re-initialize and clear the error.

E604 is a configuration communication error and does not indicate an electrical hazard or risk of component damage under normal circumstances. However, the system may restrict operation or disable certain functions while this fault is active to prevent incorrect behavior. It is best to address the configuration issue promptly to restore normal system operation.