The ECU uses two main plugs, typically referred to as the "small" and "large" connectors. The pin numbering usually starts from the top left of the header when looking directly at the ECU pins. Power and Ground Distribution
Before using this pinout, confirm your ECU: bosch me711 pinout
If you are troubleshooting a no-start condition, building a standalone harness, or reverse-engineering a stock ECU for tuning, having the accurate is non-negotiable. Below, we break down every pin on the 121-pin connector (often referred to as the "Motronic 121" connector). The ECU uses two main plugs, typically referred