the car is not running well車の調子が means “the car’s condition” or “how the car is running.” In these examples, it is followed by 悪い to mean that the car is malfunctioning or not running well. The が marks 車の調子 as the subject.
JA: 車の調子が悪いので、修理に出します。
EN: The car isn't running well, so I'll have it repaired.