[Error Code] error code c2204, Minolta c451

[glrfutures]

I have a Minolta c451 with error code: c2204. I have changed waste toner box, checked that the M20 operation, all gears are turning. I want to check the motor lock sensor: PS23; but I can't find the procedure in the manual, nor can I find a wiring diagram.(This is the first experience with this copier, and service manual).
I would appreciate any help.

thanks, glrfutures