Bosch Motronic Ecu: Pinout

| Pin # (Example) | Function / Assignment | Notes & Cross-Reference | | :--- | :--- | :--- | | | ME7.3.1 | MP 9.0 (45-pin) | ABY Engine | | 01 | — | Pin 1 (Ignition, Cyl 1) | Output to ignition coil #1. | | 03 | Fuel Pump Relay | — | Fuel Pump Relay | Switched ground to activate fuel pump. | | 07 | Air Mass Sensor | — | — | Analog input from AFM or HFM. | | 08 | Hall Sensor Signal | — | Hall Sensor Signal | Digital camshaft position signal. | | 10 | Ground (Main) | — | Ground (Main) | Major ECU ground point. | | 11 | Knock Sensor 1 | — | Knock Sensor | Piezoelectric sensor input for detonation detection. | | 12 | +5V Sensor Supply | F7 (Pot. Supply) | +5V Sensor Supply | Provides regulated 5V to throttle position, hall, etc. | | 15,16,17 | Injector #3,2,1 | F12 (CAN-L) | Injector #1,2,3 | Sequential fuel injector control (ground side). | | 18 | Permanent +12V | — | Permanent +12V | Always-on battery power for ECU memory. | | 22 | OBD (Blink Code) | — | — | Output for flashing diagnostic codes on CEL. | | 24 | — | — | Battery+ (Klemme 30) | Main power supply for ECU logic. | | 27 | — | — | Ignition On (Klemme 15) | Switched 12V that wakes up the ECU. |

Looking for a specific pinout for your Bosch ECU? Leave the Bosch part number or engine model in the comments below – we will help you track down the correct diagram.

The ECU processes these signals to calculate injection duration (pulse width) and ignition timing (dwell and advance). The dictates how these signals enter and leave the ECU. bosch motronic ecu pinout

Working with ECU hardware requires precision. A single misplaced probe can permanently damage the internal silicon drivers.

These are high-performance systems used in 1990s BMWs. Motronic 3.1 was used on the BMW M50 non-VANOS engine and has an 88-pin connector. Motronic 3.3 is a sophisticated system for V8 (M60, M62) and V12 (M70, S70) BMW engines. It often uses a dual ECU configuration for V12s. The pinout for the Motronic M3.3 on the BMW M60 V8 shows the level of specialization in these systems. Key pins include injector outputs on pins 3 (Cyl. 1), 4 (Cyl. 4), 5 (Cyl. 6), and 7 (Cyl. 7), ignition outputs on pins 22 (Cyl. 7), 23 (Cyl. 6), 24 (Cyl. 4), and 25 (Cyl. 1), heated oxygen sensor signals on pins 12 and 13, and the crucial crankshaft position sensor signal on pin 16. | Pin # (Example) | Function / Assignment

Bosch Motronic ECU remains a cornerstone of engine management, particularly for enthusiasts of vintage European performance cars. While pinouts vary significantly across generations—from early 25-pin units to complex 88-pin systems—having a reliable reference is essential for any diagnostic or tuning work. Pinout Breakdown by Generation

Representative example pinouts Note: These are representative summaries. Confirm with exact ECU number and vehicle wiring diagram before wiring or testing. | | 08 | Hall Sensor Signal |

Bosch Motronic M2.9 ECU Pinout Guide | PDF | Throttle - Scribd

Late 1980s to early 1990s (BMW E30 325i, E34 535i, Porsche 944 S2, early Volvo 940 Turbo).