Simos 33a Pinout Top [repack]

The Siemens Simos 3.3A is a common engine control unit (ECU) found in VAG group vehicles (Volkswagen, Audi, Skoda, Seat), particularly for the 1.6L petrol engines (engine code BFQ).

For Bench or OBD communication (using tools like MPPS or PCMtuner), the standard wiring for a Simos 3.3A unit typically includes: +12V Power: Connects to the main battery supply pins. simos 33a pinout top

Battery Pins (30)

• A1, A2, A3 – Must all receive +12V from the main battery or a bench power supply (13.8V recommended). If any of these are missing, the ECU will not power internal drivers.
• Current draw on bench: ~0.5–1.2A (idle) up to 8–10A (if driving injectors/coils).

4. Connector/Circuit Grouping (Top Connector)

For repair or pinout tracing, group logically: The Siemens Simos 3