Locate pin . Grounding this wire manually turns the fuel pump on without cranking. This is perfect for draining the tank or testing fuel pressure.
Check NE+ (A24) and NE- (A25) while cranking. You need an oscilloscope or a multimeter set to AC volts. You should see ~0.5V AC. No voltage? Your distributor pickup coil is dead. toyota 4afe ecu pinout
Confirmation signal sent back from Igniter to ECU validating a successful spark. Engine Speed Signal Crankshaft position/RPM signal from distributor pickup. G1 / G2 Camshaft Position Locate pin
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| Pin | Wire Color | Signal Name | Function & Notes | |-----|------------|--------------|--------------------| | 1 | Black-Red | Battery Power (B+) | Constant 12V from EFI relay. Powers ECU memory. | | 2 | White-Red | Main Relay Control | Activates EFI main relay. Pulls low to ground. | | 3 | Yellow | IG Switch (IGSW) | 12V when ignition is ON. Powers sensors. | | 4 | Brown | STA (Starter Signal) | 12V while cranking. Used for fuel enrichment. | | 5 | Black-White | Ground (E1) | Power ground for injectors and ignition. | | 6 | Black | Ground (E2) | Signal ground for sensors (TPS, MAP/MAF, temp). | | 7 | Blue-Red | VTA (Throttle Position Sensor) | 0.3–4.8V variable signal from TPS. | | 8 | Red-Blue | VC (Sensor Supply) | 5V reference output to TPS and MAP/MAF. | | 9 | Light Green | PIM (Airflow Meter Signal) | Output from MAP or volume airflow sensor. 2.5–4.5V. | | 10 | Brown-Yellow | THW (Coolant Temp Sensor) | Voltage divider output. High voltage when cold (~3V), low when hot (~0.5V). | | 11 | Yellow-Black | G- (Distributor – Crank) | One of two crank position signals (G1, G2, or G-). | | 12 | Blue | IGt (Ignition Timing Signal) | ECU sends this to igniter to fire coil. | | 13 | Red-White | IGF (Ignition Confirmation Signal) | Igniter sends back “spark occurred” confirmation. | | 14 | Violet | A/C Request (ACA) | 12V when A/C switch is ON. | | 15 | Green | +B (Sensor Power) | 12V from EFI relay for injectors and oxygen sensor heater. | | 16 | Black-White | E01 (Injector Ground) | Power ground for injector bank 1 & 2. | | 17 | White-Black | #10 (Injector 1 & 3) | ECU grounds this to fire injectors. | | 18 | Black-Yellow | #20 (Injector 2 & 4) | ECU grounds this to fire injectors. | | 19 | Yellow-Red | FC (Fuel Pump Control) | ECU grounds FC to turn on fuel pump relay. | | 20 | Gray | TE1 (Diagnostic Trigger) | Connect to E1 to flash check engine codes. | | 21 | Brown-White | W (Check Engine Light) | ECU grounds this to illuminate CEL. | | 22 | White-Black | E1 (Sensor Ground Return) | Same as pin 5–6, return for diagnostic signals. |
Check injector resistance. Unplug an injector and measure between B02-B05 and ground. Standard resistance: 13.8Ω. Shorts to ground mean a blown injector driver inside the ECU.
Throttle Position Sensor (TPS) signal and idle switch.