The invention relates to a method for detecting a malfunction of a compressed-air system, wherein a state variable is measured and is stored as a first base value and a first time stamp is captured and stored in a first step (1), the compressor (13) is activated in a second step (2), the state variable is measured and is stored as a comparison value in a third step (3), the value difference between the comparison value and the base value is formed in a fourth step (4), the value difference is compared with a threshold value in a value comparison step (5), a second time stamp is captured and the time interval with respect to the first time stamp is calculated in a sixth step (6) if the value difference is greater than or equal to the threshold value, the deviation of the time interval from a time interval reference value is determined in a time comparison step (7), and, if the deviation is outside of a tolerance interval, a malfunction is associated with the deviation in a diagnosis step (8).