The invention relates to a method for monitoring an air pressure (p) in at least one tyre (10) of a motor vehicle (K), wherein at least one air pressure (p) in the tyre (10) is detected by means of at least one measuring electronics unit (11) present in the tyre (10) and data (D) is transmitted by the measuring electronics unit (11) to a control unit (12). Depending on the data (D), the control unit (12) activates components (14, 15) of the motor vehicle (K) to generate optical and/or acoustic signals. According to the invention, the control unit (12) is switched into an after-running mode for a defined period of time when an ignition of the motor vehicle (K) is shut off, in which mode the control unit (12) can continue to receive data (D) from the measuring electronics unit (11) and, depending on the data (D), can activate components (14, 15) of the motor vehicle (K) to generate optical and/or acoustic signals. This makes it possible for a vehicle driver to actively change a tyre pressure even with the ignition key removed, whereby a danger of theft and a load on the battery during such a process is reduced.