Always pull the negative terminal before probing ECU pins.
Controls the bypass air valve to maintain idle under load.
Ensure 12V is present when the key is in the "On" position. toyota 4afe ecu pinout
Oxygen Sensor signal (monitors exhaust lean/rich conditions). VTA: Throttle Position Sensor (TPS) signal. 4. Output Actuators
Injector pulse signals. (The 4A-FE often uses "batch" firing where injectors are triggered in pairs). Always pull the negative terminal before probing ECU pins
Engine Ground (usually connected to the intake manifold).
Never use a test light on ECU pins, as the current draw can fry the internal circuitry. Oxygen Sensor signal (monitors exhaust lean/rich conditions)
Use an oscilloscope or multimeter to check for a pulse while cranking. No NE signal means no spark or fuel.
A confirmation signal sent back to the ECU to prove a spark occurred. Without this, the ECU will cut fuel. NE: Engine Speed signal (Crankshaft position).