The invention relates to a method for deterring theft of a vehicle having a three-phase electric motor without a freewheel (10), comprising the steps of using the motor in a generator mode to power a motor control circuit (14) in an initial phase of rotating the motor through motion of the vehicle; and, when the power supply level of the control circuit reaches a first threshold (Vmin), connecting by the control circuit first and second phases (b, c) of the three-phase motor continuously to a first power supply line (Vss), whereby the first and second phases are short-circuited and cause an increased braking force of the motor. During this time, the third phase of the motor may be connected to continue to supply energy to the control circuit.