Older Motronic units (M1.x) use K-Line for diagnostics. Newer units (M5.2+) transition to CAN High/Low
Let’s be blunt: guessing is not an option. A 12V power wire connected to a 5V sensor reference circuit will fry the ECU’s internal processor. A ground wire left floating on a knock sensor circuit will result in false knock detection, pulling 10 degrees of timing. Using the pinout for a Motronic M1.7 on an M3.1 system will leave your fuel pump silent. bosch motronic ecu pinout