The 4A-FE uses a rotary solenoid ISC valve with four coils (S1-S4 on pins A6-A9). The ECU grounds these coils in sequence to step the idle air bypass open or closed.
The Toyota 4A-FE ECU pinout typically follows a multi-connector configuration (often 26-pin and 16-pin or similar, depending on the specific year and model like the Corolla AE101 or AE111). This unit serves as the "brain," processing inputs from engine sensors to manage fuel injection, ignition timing, and idle speed. Key Power and Ground Terminals toyota 4afe ecu pinout
Here is the reference.
: Always disconnect the battery negative terminal before probing ECU pins. Use a back-probing tool or a T-pin to avoid damaging the terminal seals. Never pierce the wires directly. The 4A-FE uses a rotary solenoid ISC valve