Bosch Me20 Pinout Verified
If the reading is 0V or significantly below 5V, an external engine sensor may be shorted internally, pulling down the entire 5V reference circuit. Disconnect sensors one by one to see if the voltage returns to 5V.
| Pin | Signal Name | Verified Function | Behavior | | :--- | :--- | :--- | :--- | | | Injector Cyl 1 | Ground switched by ECU | 12V feed from main relay | | 3 | Injector Cyl 2 | Ground switched | 12V feed | | 4 | Injector Cyl 3 | Ground switched | 12V feed | | 5 | Injector Cyl 4 | Ground switched | 12V feed | | 8 | Ignition Coil 1 (A) | IGBT trigger | 0.5 – 3.5V dwell | | 9 | Ignition Coil 2 (B) | IGBT trigger | 0.5 – 3.5V dwell | | 10 | Ignition Coil 3 (C) | IGBT trigger (4-cyl wasted spark) | As above | | 11 | Ignition Coil 4 (D) | IGBT trigger | As above | | 16 | Idle Air Control (IAC) | Stepper motor coil 1A | 12V pulsed | | 17 | IAC Coil 1B | Stepper motor | 12V pulsed | | 18 | IAC Coil 2A | Stepper motor | 12V pulsed | | 19 | IAC Coil 2B | Stepper motor | 12V pulsed | | 24 | Main Relay Control | ECU grounds to power relay | 0V (relay ON) | | 25 | MIL (Check Engine) | Lamp ground control | 0V when active | | 30 | EVAP Purge Solenoid | PWM ground control | 12V feed present | bosch me20 pinout verified
| Connector | Critical Pin | Function | | :--- | :--- | :--- | | | Pin 1 | 5V Ref | | Black | Pin 2 | Sensor Ground | | Black | Pin 24 & 25 | Knock Sensor (Do not swap) | | Black | Pin 22 & 29 | Crank Sensor | | Grey | Pin 2-5 | Injectors | | Grey | Pin 8-11 | Ignition coils | | Grey | Pin 24 | Main Relay Control | | Brown | Pin 1-3 | ECU Power Ground | | Brown | Pin 4-5 | Permanent 12V | | Brown | Pin 30 | K-Line (Diagnostic) | If the reading is 0V or significantly below