Auto check control monitors the condition of certain components on the vehicle such as the brake system, coolant level or engine oil pressure. This takes place continuously when the ignition is switched on. Malfunctions and servicing requirements are shown on the driver information system (DIS) display, accompanied by warning tones. The displays are prioritised with either red or yellow illuminated symbols. The red signals indicate a potentially hazardous situation, the yellow ones are merely cautionary. In addition to the red symbols, information for the driver is displayed in certain situations.