This is the 11359th most frequent Russian word.
диагностику
"Диагностику" translates to "diagnostics" in English, referring to the process of identifying or analyzing a condition or issue.
The word "диагностику" is used here in the accusative case as the object of the verb "записаться", referring to a car diagnosis service.
Я записался на диагностику автомобиля в сервис.
I scheduled a car diagnosis at the service center.
In this sentence, "диагностику" is in the accusative case, as it is the direct object of the verb "проведет", specifying health diagnosis.
Диагностику состояния здоровья проведет врач.
The doctor will carry out the health diagnosis.
Here, the word "диагностики" is used in the genitive case to indicate what kind of diagnosis is being referred to, i.e., equipment needed for the diagnosis.