Triggers the circuit opening relay to activate the fuel pump. Check Engine Light Controls the dashboard Malfunction Indicator Light (MIL). Connector B (Engine Sensors and Inputs) Signal Name Function Description PIM MAP Sensor Signal
Grounding circuit for Fuel Injector Cylinder 1 (or pair 1/3). Injector Driver 2
The 4AFE uses a distributor-based ignition system with electronic spark advance. Unlike modern direct ignition engines, it relies on a dedicated set of signals between the ECU, the distributor (with integrated cam and crank sensors), the airflow meter, and the injectors. toyota 4afe ecu pinout
Toyota updated the 4A-FE engine and its management system multiple times. You must identify your engine's generation before pinning out the ECU, as wire colors and plug layouts changed significantly. 1. Generation 1 (1987–1992)
Typically yellow or grey plugs arranged in a 10p-18p-14p or 26p-16p configuration. Generation 2 (1993–1998) Triggers the circuit opening relay to activate the fuel pump
Measure voltage between VCC and E2 with the key ON. It must read exactly 4.5V to 5.5V . If this voltage is shorted to 0V or reads 12V, the ECU is damaged or a sensor is internally shorted.
Because the 4A-FE is primarily an OBD-1 era engine, reading codes does not require a complex scanner. Injector Driver 2 The 4AFE uses a distributor-based
Generally uses a 26pin - 16pin - 22pin configuration. Generation 3 (1997–2002)
#10 (Injector 1): Injector output for Cylinder 1. #20 (Injector 2): Injector output for Cylinder 2. #30 (Injector 3): Injector output for Cylinder 3. #40 (Injector 4): Injector output for Cylinder 4. IGT (Ignition Timing): Signal from ECU to igniter.
Pull codes (using TE1 and E1 in the diagnostics box) to identify the faulty sensor.
Ground your multimeter to a clean bare metal chassis point or the pin.