Modern vehicles are rolling networks where dozens of ECUs constantly talk to...

https://www.mediafire.com/file/77eba7osq6tv0c5/pdf-93939-6247.pdf/file

Modern vehicles are rolling networks where dozens of ECUs constantly talk to each other. When a warning light pops up, a basic code reader only gives you a vague hint. You need real diagnostic software to see live data streams and bidirectional controls