E4: Error Code

The E4 error code indicates a communication error between the toilet and the heater.
 

Possible Cause

Several reasons can cause this error. It could be that the toilet is not connected to the heater properly, or the connection has become loose. It could also indicate an issue with your toilet's motherboard.
 

Solution

When this happens, reach out to customer service for assistance. You can submit a form if the device is still under manufacturer warranty. Remember to provide your order number, the device serial number, and a video of the problem when submitting the claim.