"出现机能障碍" can be translated as "experience dysfunction" or "develop dysfunction" in English, depending on the context.
"Experience dysfunction" implies that someone or something is undergoing a state of impaired function.
"Develop dysfunction" suggests that dysfunction has arisen or formed over time.
For example:
"The patient is experiencing dysfunction in his nervous system." （患者神经系统出现机能障碍。）
"Prolonged stress can lead to the development of dysfunction in various bodily systems." （长期压力可能导致身体多个系统出现机能障碍。）