An elevator includes a car with at least two car doors, each car door being provided with a door contact, a shaft being provided with corresponding landing doors, each landing door being provided with a door contact, each landing door opening in synchronism with the corresponding car door, the door contacts forming part of a safety circuit of the elevator, a car door contact input being connected to a middle point in the safety circuit between a series connection of the car door contacts and a series connection of the landing door contacts. A status information of the car door contact input is monitored in order to determine whether the door contacts are operational or not when the car doors are opened and/or closed with a predetermined time delay at a landing.