The Bosch ME20 uses a high-density multi-plug connector system. Pin numbers are molded directly into the plastic housing on both the wire harness side and the ECU header pins.
Option 2: The "Short & Technical" (Best for Facebook Groups/Discord) Bosch ME2.0 Verified Bench Pinout 🛠️
Now, I'll write the article. The Definitive Guide to the Verified Bosch ME20 ECU Pinout
: This ECU uses a hardwired "Terminal 50" (starter activation) rather than CAN-bus signals for its start enable, making it a popular choice for engine swaps where the original immobilizer system is missing. Immo Off - ECU Bosch ME2.1 / ME2.0 Mercedes | CARLABIMMO CarLabImmo Mercedes-Benz ECU Wiring Diagrams - Black Smoke Ltd Black Smoke Pinout Bosch ME2.0 Mercedes | XTuning XTuning.vn bosch me20 pinout verified
Disclaimer: Always verify against your specific ECU revision. Electrical testing should be performed by qualified personnel.
Wakes up the main processor. Verified Pin: Plug 1, Pin 3 2. Communication Interfaces
ME20 CONNECTOR B (16-pin): B1-4: Injectors 1-4 | B9: Coil 1+4 | B10: Coil 2+3 The Bosch ME20 uses a high-density multi-plug connector
| Pin | Signal | Verified Function | Notes | | :--- | :--- | :--- | :--- | | | | | | | 3 | Ground | ECU Main Ground (Sensor) | Must be clean. Do not share with injectors. | | 8 | Ground | Power Ground (Injectors/Coils) | Heavy gauge wire. | | 37 | B+ | Permanent 12V (Memory) | Fused at 5A. | | 54 | B+ | Main Relay 12V (Power) | Switched via Motronic relay (Pin 56). | | SENSORS | | | | | 4 | TPS | Throttle Position Signal (0-5V) | Verified linear sweep. | | 21 | MAP | Manifold Absolute Pressure | 1-4.5V linear. | | 22 | IAT | Intake Air Temp (NTC) | ~2.5k Ohms @ 20°C. | | 40 | CLT | Coolant Temp (NTC) | Same curve as IAT. | | 52 | CKP | Crank Speed Sensor (Shielded) | VR sensor. Polarity matters! | | 43 | CMP | Cam Sensor | Hall effect (0-5V square wave). | | 50 | KS | Knock Sensor 1 | AC voltage. Shield to Pin 49. | | ACTUATORS | | | | | 7 | Injector 1 & 4 | Ground side switching | Saturated drivers (No ballast). | | 9 | Injector 2 & 5 | Ground side switching | | | 11 | Injector 3 & 6 | Ground side switching | | | 13 | Fuel Pump Relay | Ground trigger | Activates prime for 2 seconds. | | 23 | Ignition Output 1 | Coils 1 & 6 (Wasted spark) | Confirmed logic level (5V). | | 24 | Ignition Output 2 | Coils 2 & 5 | | | 25 | Ignition Output 3 | Coils 3 & 4 | | | 56 | Main Relay Control | Ground trigger | Switches Pin 54 power. |
Note: This document summarizes a verified pinout for the Bosch ME20 engine control unit (ECU), along with wiring notes, common signals, testing tips, and safety/diagnostic considerations. Use it for reference during bench-testing, wiring harness repair, diagnostics, or retrofit projects. Confirm with continuity testing and the specific ECU label/connector before making permanent wiring changes.
To power up the ECU on a bench for communication (OBDII/K-Line), use the following pin assignments on the main connectors. Connection Type Pin Number Wire Color (Typical) Pin 1 (Large Connector) Red / Green +12V Ignition (15) Pin 2 (Large Connector) Pink / Red Ground (31) Pin 4 (Large Connector) K-Line (Diagnostics) Pin 19 (Large Connector) White / Yellow 🛠️ Connector Layout & Identification The Definitive Guide to the Verified Bosch ME20
: Main Relay Control — Ground output signal from ECU to trigger the power relay.
involves using a Julie™ Emulator to bypass the factory immobilizer (IMMO OFF), which requires precise wiring to the K-line and power pins.