A handheld power tool comprising: - a driving means for driving a tool of said handheld power tool , wherein said driving means is an internal combustion engine, - a control system of the handheld power tool , the control system comprising at least one electronic control unit, ECU for controlling the driving means, - a stop button switch for stopping said driving means, - a cable arrangement for connecting the stop button switch and the ECU , the cable arrangement comprising a power tool connector and a stop button connector configured to mate with each other, the power tool connector and the stop button connector being referred to as connectors, where the cable arrangement and the handheld power tool are adapted: - when the connectors are connected, to connect the stop button switch to the ECU , - when the connectors are disconnected, to disconnect the stop button switch from the ECU , characterized in that the cable arrangement and the handheld power tool are adapted: - to connect the power tool connector with a service tool connector of a service tool assembly when the connectors are disconnected, and - by connecting the service tool connector and the power tool connector , to establish a data communication between a computing device of the service tool assembly and the ECU of the handheld power tool , wherein the computing device is provided externally of the handheld power tool . - a driving means for driving a tool of said handheld power tool , wherein said driving means is an internal combustion engine, - a control system of the handheld power tool , the control system comprising at least one electronic control unit, ECU for controlling the driving means, - a stop button switch for stopping said driving means, - a cable arrangement for connecting the stop button switch and the ECU , the cable arrangement comprising a power tool connector and a stop button connector configured to mate with each other, the power tool connector and the stop button connector being referred to as connectors, where the cable arrangement and the handheld power tool are adapted: - when the connectors are connected, to connect the stop button switch to the ECU , - when the connectors are disconnected, to disconnect the stop button switch from the ECU , characterized in that the cable arrangement and the handheld power tool are adapted: - to connect the power tool connector with a service tool connector of a service tool assembly when the connectors are disconnected, and - by connecting the service tool connector and the power tool connector , to establish a data communication between a computing device of the service tool assembly and the ECU of the handheld power tool , wherein the computing device is provided externally of the handheld power tool . - when the connectors are connected, to connect the stop button switch to the ECU , - when the connectors are disconnected, to disconnect the stop button switch from the ECU , - to connect the power tool connector with a service tool connector of a service tool assembly when the connectors are disconnected, and - by connecting the service tool connector and the power tool connector , to establish a data communication between a computing device of the service tool assembly and the ECU of the handheld power tool , wherein the computing device is provided externally of the handheld power tool . <EOS>