## 4 Experimental Results  
The ability to transmit DTC codes at predetermined intervals allows for an effective analysis of both the simulator and the communication protocol's performance. Initially, tests were conducted using the DTC code simulator. The 'Generate and Send DTC' function was used with various codes, such as P0700, P0300, P0172, P0500, P0420, P0335, P0325, and P0340--common codes across manufacturers like Chevrolet, Ford, Nissan, and Toyota. For instance, the P0300 error code, classified by Nissan as 'Cylinder misfire detected in random cylinders', was generated as a test case (see Figure 7c,d), and the simulator responded accurately when the 'Send DTC' button was clicked. Additionally, the simulator's 'Send DTC randomly' function was tested by sending 100 DTC codes. As shown in Figure 7c,d, the simulator successfully responded, transmitting 100% of the codes. Finally, Figure 9 illustrates the functional prototype used for both laboratory and field tests, where the transmitter (Tx) and receiver (Rx) were placed in the same location for controlled testing. Figure 8: DTC transmitter flow datagram. Tests were carried out to assess communication between the Tx subsystem (where DTC codes were generated using the simulator, as shown in Figure 10) and the Rx subsystem (see Figure 11) over a fixed route of 15.5 km. The simulator was programmed to wait for an acknowledgement (ACK) from the Rx subsystem after sending a DTC code. Depending on the ACK response--whether positive or negative--the Tx subsystem either resends the same DTC code or generates a new one randomly, as required. These tests aimed to evaluate the communication protocol's efficiency in transmitting and receiving DTC codes, considering the conditions of the 2G cellular network used during the trials. The diagram in Figure 12 shows the sending and receiving of data, sending the 85 codes, which resulted in a loss of 18 codes, these were not received due to poor signal quality or poor latency, it is worth mentioning that the vehicle was driven at an average speed of 45 miles per hour. However, 67 codes were received, achieving an effectiveness of 78.82%. For these tests, a route on 15.5 km was taken (see Figure 13). According to the results presented in Table 9, it is shown that the communication protocol is 78.82% effective, that is, the more codes are sent, the lower the effectiveness. However, this means that with the effectiveness of 78.82%, 67 codes of the 85 codes sent were received using 2G technology, as presented in Table 10. In Figure 13, points A to G (each one represents a 2G communication tower) allow the data to reach its destination. During the vehicle's journey, it is observed that there is infrastructure for 2G technology (from point A to G), this allows communication to be established between the vehicle and the infrastructure, so that if the vehicle has an accident or stops due to a mechanical failure, it can send data or a message for a rescue to be carried out. In Figure 14, the same route taken by the 15.5 km vehicle is shown, in which it can be observed that in a 10 km route there is no 5G technology infrastructure (from point A to B as shown in Figure 14) and the data does not reach its destination because there is no coverage, 0 codes were received out of the 85 codes sent, that is, the vehicle is left without communication, therefore, in the event that the vehicle suffers a mechanical failure or accident, it will not be able to establish cellular communication so that the rescue team can reach the emergency. Not receiving data with 5G technology on the journey from point A to point B means that there is 0% effectiveness, because there is no coverage in that territory. Figure 9: System connection with Tx in motion. Figure 11: Tests with the connection of subsystem Rx. Figure 12: Diagram of sending and receiving data. Figure 10: Tests with the connection of subsystem Tx.