A method of defense against an attack relay action on a remote activation of a function present in an automotive vehicle. The attack relay receives a frame of electromagnetic waves emitted by the activation module and retransmits it to the at least one activation device, nevertheless out of range of emission of the activation module, which dispatches a response frame of electromagnetic waves to the activation module. There is performed, out of range of emission of the activation module, an at least partial interception of a retransmitted frame of electromagnetic waves originating from the attack relay in the direction of the activation device. An at least partial destruction of the retransmitted frame at the activation device and/or of the response frame of the activation device toward the activation module rendering the activation of the function inoperative is performed.