Method for secure signal manipulation for testing integrated safety functionalities of a software-based motor vehicle component in a motor vehicle, characterized by the steps of: selecting at least one first input signal (V') present at an input of a software-based motor vehicle component evaluated with a risk level of ASIL A to ASIL D according to ISO standard 26262 for a safety analysis of a safety function of the motor vehicle component, wherein the first input signal (V') present at the input corresponds to a first control signal generated by the motor vehicle; determining at least one first test signal by changing the selected at least one first input signal (V'); providing an external signal manipulation unit for verification and validation tests of the safety function of the motor vehicle component by means of the determined, at least one, first test signal in a QM context; interrupting the connection of the motor vehicle component to the motor vehicle, and establishing a connection with the signal manipulation unit, so that the first test signal is present at the input of the motor vehicle component instead of the first input signal (V'); performing the verification and validation tests of the safety function of the motor vehicle component by means of the at least one first test signal using standardized XCP services, wherein the output signal (F') respectively present at an output of the motor vehicle component is detected by the signal manipulation unit; checking the verification and validation tests performed with the signal manipulation unit outside of the motor vehicle component, by means of a third test signal provided by the signal manipulation unit and a target output signal of the motor vehicle component; adapting the at least one first and third test signal (W1, W3) by means of a further external signal manipulation of the respectively selected signal (V, F), and repeating steps and with the manipulated test signals (W1, W3) if necessary until the respective output signal (F') corresponds to the target output signal; clearing the tested safety function by interrupting the connection of the signal manipulation unit to the motor vehicle component and restoring the connection of the motor vehicle component to the motor vehicle via the at least one input and the output of the motor vehicle component. selecting at least one first input signal (V') present at an input of a software-based motor vehicle component evaluated with a risk level of ASIL A to ASIL D according to ISO standard 26262 for a safety analysis of a safety function of the motor vehicle component, wherein the first input signal (V') present at the input corresponds to a first control signal generated by the motor vehicle; determining at least one first test signal by changing the selected at least one first input signal (V'); providing an external signal manipulation unit for verification and validation tests of the safety function of the motor vehicle component by means of the determined, at least one, first test signal in a QM context; interrupting the connection of the motor vehicle component to the motor vehicle, and establishing a connection with the signal manipulation unit, so that the first test signal is present at the input of the motor vehicle component instead of the first input signal (V'); performing the verification and validation tests of the safety function of the motor vehicle component by means of the at least one first test signal using standardized XCP services, wherein the output signal (F') respectively present at an output of the motor vehicle component is detected by the signal manipulation unit; checking the verification and validation tests performed with the signal manipulation unit outside of the motor vehicle component, by means of a third test signal provided by the signal manipulation unit and a target output signal of the motor vehicle component; adapting the at least one first and third test signal (W1, W3) by means of a further external signal manipulation of the respectively selected signal (V, F), and repeating steps and with the manipulated test signals (W1, W3) if necessary until the respective output signal (F') corresponds to the target output signal; clearing the tested safety function by interrupting the connection of the signal manipulation unit to the motor vehicle component and restoring the connection of the motor vehicle component to the motor vehicle via the at least one input and the output of the motor vehicle component.