If there are notches worn into the splines, replace the sub clutch hub. Also, replace the steel plates if their teeth are damaged.

Clutch Housing Finger Inspection
Damper Cam InspectionKIBS Hydraulic Unit Communication Error (Service Code 1b, KIBS Equipped
Models)
KIBS Hydraulic Unit Communication Line Inspection
When the data (for status of KIBS hydraulic unit) is not
sent from the KIBS hydraulic unit to the meter unit and
ECU, the service code 1b is displayed.
The data is sent through the CAN communication line.
The service code 1b is detected with the ...
Check 3-1: CAN Communication Line Resistance Inspection
Set the hand tester [A] to the ×1 Ω range and connect it
to the terminal [11] and [12] in the meter unit.
Special Tool - Hand Tester: 57001-1394
CAN Communication Line Resistance (at Meter Unit)
Standard: 122 126 Ω
If the tester reading is not specified, replace the meter ...
Starter Clutch Inspection
Remove:
Torque Limiter Cover (see Torque limiter Removal)
Turn the torque limiter [A] by hand. The torque limiter
should turn forward freely [B], but should not turn backward.
If the starter clutch does not operate as it should or if it
makes noise, go to the next step.
Disassem ...