Well, your suggestion of "The actual physical position of the actuator (i.e. the percentage of 'winding') must exactly match the last position that the EPB controller previously saved." seems to be correct. I was curious to know why it might have happened and repaired the old actuator and connected and there you go. All the error codes disappeared because the old Actuator position matches the EPB Controller configuration. This confirms that the EPB Module is still functional, and I still need to replace the actuator with a new one. Thank you very much for the suggestion.
Just FYI, This is what the repair manual suggests.
If the electric parking brake control module is replaced, perform the automatic configuration and related parts check using the following procedure.
(1) Switch the ignition ON (engine off or on) and wait for 30 s or more.(2) Switch the ignition off and wait for 3 s or more.(3) Switch the ignition ON (engine off or on) to allow the electric parking brake control module automatic configuration to be completed.(4) Using the M-MDS, perform a DTC inspection and verify that DTCs U2300:55/U2300:56 are not displayed. (See
DTC INSPECTION [ELECTRIC PARKING BRAKE].)
• If DTCs U2300:55/U2300:56 are displayed, go to the DTC troubleshooting procedure. (See
DTC TABLE [ELECTRIC PARKING BRAKE].)
(5) Operate the electric parking brake and perform the related parts check.(6) Release the electric parking brake.(7) Verify that the brake system warning light and the electric parking brake warning light turn off.
• If the brake system warning light and the electric parking brake warning light do not turn off, perform a DTC inspection because an electric parking brake malfunction may have occurred. (See
DTC INSPECTION [ELECTRIC PARKING BRAKE].)
(8) Operate the electric parking brake again.(9) Verify that the brake system warning light turns on and the electric parking brake warning light turns off.
• If the brake system warning light does not turn on or flashes, or the electric parking brake warning light does not turn off, perform a DTC inspection because an electric parking brake malfunction may have occurred. (See
DTC INSPECTION [ELECTRIC PARKING BRAKE].)