Looking at the back of the plastic plug where the wires physically enter the harness. Pin Numbering Conventions
One of the most common mistakes in automotive wiring is misidentifying the pin orientation, which can instantly destroy an ECU via reverse polarity. Bosch Ecu Pinout Datasheet
The primary differential data highway used to talk to the transmission control module, ABS, instrument cluster, and body control modules. Looking at the back of the plastic plug
Understanding the generation dictates how you will interact with the pins. For example, older units frequently use standard K-Line communication for diagnostics, while modern MG1 units rely entirely on high-speed CAN-Bus or Ethernet protocols. 3. How to Read a Bosch Pinout Schematic Bosch Ecu Pinout Datasheet
Looking at the female terminals of the plastic plug detached from the ECU.