Simos 33a Pinout Top May 2026
Siemens Simos 3.3A (06A 906 033 A)
The is a legacy engine control unit (ECU) found primarily in the Audi A3 8L and Volkswagen Golf Mk4 with the 1.6L 8V (102HP) petrol engine. Its pinout configuration is essential for technicians performing bench-top diagnostics, IMMO-off procedures, or EEPROM/Flash reading. Technical Overview
Primary Application:
The Simos 3.3A belongs to the Simos 3 family, which is known for its relatively straightforward hardware but sensitivity to specific communication protocols when accessed via bench tools. Audi A3 I (8L), VW Golf IV 1.6i. simos 33a pinout top
Terminal 30 (12V+)
Pro Tip for Bench Testing: When powering the SIMOS 33A on a bench, you need to supply and Terminal 15 (Ignition 12V+) , along with a solid **Ground Siemens Simos 3
- Pin 1: Main Relay Supply (Terminal 30) – Battery Constant Positive (+12V).
- Pin 2: Ground (Terminal 31) – Main ECU Ground (Chassis/Engine Block).
- Pin 3: Ground (Terminal 31) – Secondary Ground.
- Pin 6: Ignition Switch Supply (Terminal 15) – Switched +12V (This "wakes up" the ECU).
- Pin 12: CAN High (Drive train CAN bus).
- Pin 13: CAN Low (Drive train CAN bus).
