Samsung dishwasher e3 error code

The E3 error occurs when the temperature of the water entering the machine exceeds 176F

Not unlikely, the water heater in your house is set at a high temperature mode (water temperature exceeding 120F). If it is, please, set it at a lower temperature. However, if the temperature of the inlet water is normal (not exceeding 176F), there is a problem with the temperature sensor, so take steps to replace it. If the replacement does not work either, you need to replace the main PBA.