Display shows ERR4 and time or regeneration settings cannot be saved

Safety: Unplug the softener before removing the control panel or touching internal electronics.

Steps:

• Power cycle: Disconnect power for 10 minutes, then reconnect. Attempt to set the time and regeneration parameters again. If ERR4 returns, continue.
• Check supply voltage: Verify the outlet provides a stable 120 VAC (or local standard). Avoid using long extension cords or shared outlets with heavy loads.
• Inspect keypad: Remove the control panel cover. Check for moisture, salt corrosion, or physical damage on the keypad membrane and ribbon cable. Ensure the ribbon is fully seated in the control board connector.
• Clean connectors: If corrosion is present, gently clean the board edge connector and ribbon contacts with isopropyl alcohol and allow to dry completely.
• Test keypad response: With power restored, press each button and confirm the display responds. If some keys do not respond or ERR4 appears when pressing certain keys, the keypad membrane is likely defective.

Resolution: Replace the electronic control board if settings will not save or ERR4 persists after keypad and power checks. On some Whirlpool Pro Series models, the keypad and board are a single integrated assembly and must be replaced together.