A self-healing software system is an advanced computer program or system designed to detect, diagnose, and automatically recover from faults or errors without human intervention. These systems are typically employed in mission-critical applications where downtime can have significant financial or operational consequences. Failure detection is one of the important steps in the self-healing system. In this research, a method using runtime verification is proposed to diagnose four types of errors at the component level. The simulation on mRUBIS shows that the suggested method has the necessary efficiency in detecting the occurrence of failures.