Never connect E2 to chassis ground. It will introduce voltage offset and corrupt your sensor readings. Always keep sensor grounds running directly back to pin B12.
| Pin | Type | Signal Name | Function | |:---:|:---:|:---:|:---| | 3 | Input | | Engine Coolant Temperature Signal | | 5 | Input | THA | Intake Air Temperature Signal | | 4 | Input | PIM | Intake Manifold Pressure Signal (for some markets) | | 7-8 | Input | VTA / VCC | Throttle Position Sensor Signal | | 9 | Input | NE | Crankshaft RPM Signal (from distributor) | | 21 | Input | NE (Alt.) | RPM Signal (alternate pin) | | 10 | Input | OX | Oxygen Sensor (Lambda) Signal | | 23 | Input | KNK | Knock Sensor Signal | | 16 | — | E2 | Sensor Ground (return for sensors) | | 24 | Ground | E1 | Computer Ground (main ground) | 4s-fe ecu pinout
: Throttle Position Sensor (TPS). VCC provides a stable 5V reference to the sensor. VTA sends back a variable voltage corresponding to how far the throttle is open. IDL signals the ECU when your foot is completely off the gas pedal. Never connect E2 to chassis ground