The Simos 33A ECU uses a 154-pin Tyco / AMP connector (often referred to as the "Tyco 154-pin header"). The connector is physically large and rectangular, with pins arranged in several rows. When the ECU is mounted in the car, the connector faces downward. However, when you remove the ECU and flip it over for bench work, the top side refers to the side of the connector where the plastic housing mates with the ECU’s circuit board.
From the top perspective (looking directly at the open connector face with the locking lever oriented correctly), pins are organized into: simos 33a pinout top
⚠️ Important: There are multiple hardware revisions of the Simos 33A (e.g., 33A.6, 33A.7, 33A.12). While pin assignments are largely consistent, always verify with wiring diagrams specific to your vehicle model. The Simos 33A ECU uses a 154-pin Tyco
┌─────────────────────────────┐
│ │
Row A │ 01 02 03 ... ... ... 14 15 │ (Top/Component side)
Row B │ 16 17 18 ... ... ... 29 30 │
Row C │ 31 32 33 ... ... ... 44 45 │
Row D │ 46 47 48 ... ... ... 59 60 │ (Bottom/Solder side)
│ │
└─────────────────────────────┘
When looking at the ECU with the connectors facing you and the mounting tabs at the top, the plugs are usually arranged from left to right. Below is a breakdown of the critical pins found in the standard layout. ⚠️ Important: There are multiple hardware revisions of
Note: Pin locations can vary slightly between hardware revisions. Always look for the pin numbers stamped on the ECU plastic housing next to the connector slots.
🔧 Pro tip: For bench flashing, wire a 10A fuse in series with A1–A3. Many tuners accidentally short A7 to ground and fry the ignition sense circuit.