Simos 33a Pinout Top Best Guide
The hardware is robust and rarely suffers from internal component failure compared to newer, more complex units. Cons:
When working with the top view , always ensure no metal tools touch two adjacent pins. The Simos 33A operates at 5V logic levels; a short between 5V_REF (Pin 31) and Sensor GND (Pin 30) will instantly destroy the 5V regulator. simos 33a pinout top
| Pin # | Signal Name | Wire Color (Typical) | Function | Top-Side Test Point | | :--- | :--- | :--- | :--- | :--- | | | | 1 | KL30 (B+) | Red/Yellow | Main battery voltage (constant 12V) | Near large capacitor | | 2 | KL30 (B+) | Red/Yellow | Second main power input | Near power FETs | | 3 | KL31 (GND) | Brown | Power ground (high current) | TP1 (often) | | 4 | KL31 (GND) | Brown | Second power ground | TP2 | | 5 | KL15 (IGN) | Black/Violet | Ignition switched 12V (wake-up) | Resistor divider area | | CAN Bus & Communication | | 23 | CAN_L (Powertrain) | Orange/Brown | Low-speed CAN bus (500 kbps) | TP23 | | 24 | CAN_H (Powertrain) | Orange/Black | High-speed CAN bus | TP24 | | 25 | K-Line (Diagnostic) | Violet/Yellow | ISO 9141 (legacy diagnostics) | TP25 | | Sensors (5V Reference) | | 30 | Sensor GND | Brown/Blue | Analog sensor ground | TP30 | | 31 | 5V_REF1 | Yellow/Red | 5V supply for MAP, APP, etc. | TP31 | | 32 | 5V_REF2 | Yellow/Brown | 5V supply for EGT, Rail Pressure | TP32 | | Actuators | | 48 | Injector Cyl 1 | Brown/Green | High-side driver output | Near MOSFET driver | | 49 | Injector Cyl 2 | Brown/Yellow | High-side driver output | Near MOSFET driver | | 50 | Injector Cyl 3 | Brown/Grey | High-side driver output | Near MOSFET driver | | 51 | Injector Cyl 4 | Brown/White | High-side driver output | Near MOSFET driver | | 60 | Ignition Coil 1 | Black/Green | IGBT gate drive | TP60 | | 61 | Ignition Coil 2 | Black/Yellow | IGBT gate drive | TP61 | | 62 | Ignition Coil 3 | Black/Grey | IGBT gate drive | TP62 | | 63 | Ignition Coil 4 | Black/White | IGBT gate drive | TP63 | | Oxygen Sensors (Lambda) | | 71 | Heater Control (Bank1) | White/Red | O2 sensor heater ground side | TP71 | | 72 | Pump Current+ (UEGO) | Grey/Blue | Wideband control | TP72 | | 73 | Virtual GND | Grey/Brown | Sensor reference | TP73 | | 74 | Pump Current- | Red/Blue | Wideband return | TP74 | The hardware is robust and rarely suffers from
