Error code I have a Ricoh afficio 2232c and I am getting the error code sc393-01. Suggestions please

SC No. Item Definition Possible Cause Related
SCs Troubleshooting Procedure Type
SC
393-
001
TD sensor error
during warming
up
393-001: K
393-002: Y
393-003: C
393-004: M
The development-unit drive
starts. TD sensor signal is 0.78
V or less.
• Loose cable
connection
• Positioning plate out
of place
• Defective TD sensor
• Development unit not
found
1. Turn the main switch off and on.
2. Check that the development unit is
correctly installed.
3. Remove the development unit and
check the connector on the rear.
4. Check the positioning plate.
5. Replace the development unit.

Hope this can help you , seems the problem is on the black development unit