Display shows “Err 02” and the unit will not advance through regeneration cycles.

Safety first: Disconnect power and close the inlet valve. Bypass the softener using the AO Smith bypass valve to maintain house water if needed.

Inspect the drive motor and cam:

• Remove the cover: Take off the top/front cover to expose the control valve and motor assembly.
• Locate the drive motor: On AO Smith softeners, the motor is typically mounted on the side of the control valve with a small gear driving a larger cam or rotor.
• Check for mechanical binding: Try to gently rotate the main cam/rotor by hand (only slightly). If it is completely stuck, there may be resin beads or debris in the valve body. Do not force it; forcing can crack the valve.
• Inspect gears: Look for stripped plastic gears or a loose motor mounting screw. If gears are damaged, the motor/gear assembly should be replaced.
• Test motor operation: Restore power briefly with the cover off and initiate a manual regeneration. Observe whether the motor attempts to turn. If it hums but does not move, it is likely failing.
• Check motor wiring: Ensure the motor connector is fully seated on the control board and wires are not pinched or broken.

Corrective action: Replace the drive motor assembly if it does not run or if gears are stripped. If the motor runs but the cam does not move, inspect and replace the rotor/cam kit or the entire control valve head as needed.