WE HAVE ALREADY SEEN SEVERAL EXAMPLES of data download via on-vehicle diagnostic ports or individual ECU umbilicals. For some systems, after the scanner interface has connected via the specific network protocol, it is possible to download the entire EEPROM contents of a target ECU (given the right interrogation command codes). Such a download is shown in Fig. 3.18. In other systems, the target ECUs must be interrogated using an umbilical cable from the scanner directly to the ECU, or by inserting the ECU in a laboratory fixture. Such downloads are shown in Figs. 3.19 and 3.20.