I have faced this problem before and typically the 400K Fuser PM kit would resolve it. I have one PRO C900 only and have struggled with this error reoccurring randomly the past year regardless of what maintenance has been done. It has occurred again and I am at a loss as to what I am missing.
What I have observed is during warmup the Oil Supply Motor may "hesitate" while turning. Yesterday, the machine went through a 6 minute warmup and during the last 3 or 4 seconds before the Fuser Motor stopped turning the Oil Supply Motor hesitated during its rotation. I was in back of the machine to observe this but also had a VOM on the Yellow pin on the Oil Motor. In standby there is 24.1 V on the pin and during the ON state goes to 22.9 V - 23.1 V. The voltage was there during the whole time the Fuser Motor was ON which is as it should be - the Oil Supply Motor ONLY drives when the Fuser Motor is ON. SC 558 was generated at this point.
I have had Ricoh Tech Support involved with this a year ago but it has never been successfully resolved. Here is at list of the current "fix" history:
(1) Replaced Oil Supply Motor Assy (include Motor Coupling) and Sensor.
(2) Replace Brass Bushings on Mech Plate that align the Fuser Unit (to make sure it is not binding when closing).
(3) Fuser 400K and 800K PM Kits replaced. This includes the Oil Application Gear Kit and Fusing Belt Tension Roller (installed in correct screw holes).
(4) Both Oil Pumps, Oil Tank and Fuser Oil (all fresh Oil) replaced.
(5) Silver and Black Springs on the Oil Application Unit in the correct position and NOT damaged.
(6) Confirm Wall Voltage and Oil Pump Connector position on PS. Oil lay down sufficient and set according to birth certificate.
(7) Couplings for Fuser drive and Oil Motor drive engaging OK (no binds).
(8) Set Heating Roller and Pressure Roller Low Power Mode to 110 deg. (both were at 0). This was done in case the oil on the Fusing Belt is causing the Oil Application Roller to stick.

I think that about covers it. This doe not appear to be an I/O PCB problem. I DO NOT HAVE A BACKUP FUSER UNIT I CAN INSTALL. Any solutions out there would be greatly appreciated.