My OKI C9600 printer has problem related to led head with error code 133. This error msg indicates Cyan led head is failed.
There are some reasons that leading to this failure. One of them might be caused by drum. If drum is dirty or is overflown by toner.
So you may test C Led head to know if it is OK. How to test ? Try changing with another Led Head such as Y,K, M.
This is the way I did, and my printer is OK now.