Dust or toner buildup on the "U-shaped" HP sensor can prevent it from detecting the actuator.
The pressure release motor may be locked due to an excessive load, or the motor driver itself could be defective. sc569-00 ricoh
When this error appears, it typically points to a mechanical or electrical failure within the fuser unit's pressure release system. Dust or toner buildup on the "U-shaped" HP
The pressure roller HP sensor (often designated as S26 or SEN60) may be disconnected, dirty, or defective. sc569-00 ricoh