Controls the bypass air valve to maintain idle under load.
Below are the most critical pins you will encounter when wiring or troubleshooting. Note that colors may vary slightly by year, but pin locations generally remain consistent within specific generations. 1. Power and Ground Signals These pins ensure the ECU turns on and stays grounded. 12V Switched Power (from the EFI main relay). BATT: Permanent 12V Power (for memory/fault codes). toyota 4afe ecu pinout
The signal from the MAP sensor. THA: Intake Air Temperature sensor signal. THW: Coolant Temperature sensor signal. Controls the bypass air valve to maintain idle under load
Always pull the negative terminal before probing ECU pins. BATT: Permanent 12V Power (for memory/fault codes)
Transmission controls and auxiliary signals. Plug C (22-pin): Dashboard interface and diagnostic pins. Essential Pin Descriptions and Functions
Use an oscilloscope or multimeter to check for a pulse while cranking. No NE signal means no spark or fuel.