Crankshaft and camshaft position signals coming from the pickup coils inside the distributor (or separate block sensors on later models). Engine Sensors

Throttle Position Sensor (TPS) outputs indicating throttle angle and idle state. 4. Auxiliary and Diagnostic Pins

Before splicing any wires, you must identify the specific generation of your 3S-FE engine. Toyota produced this engine from 1986 until the early 2000s, updating the fuel injection, ignition, and ECU architectures multiple times.

While exact pin locations vary by part number, Toyota ECUs share standard acronyms stamped directly onto the internal circuit board (PCB). If you open the ECU casing, you will often see these labels printed next to the solder joints. 1. Power Supply and Ground Circuit

While a direct, single-file PDF is rare, here are the best methods to find the exact diagram you need.

Before you begin any electrical diagnostics or modification, it is critical to follow these safety guidelines:

Sensor ground return lines (critical for preventing signal noise on the TPS and MAP sensors).

Before splicing any wires, you must identify the specific generation and market origin of your 3S-FE engine. Toyota updated the electronics, ignition systems, and emissions controls multiple times throughout the engine's production run. 1. Generation 1 & 2 (Late 1980s to Early 1990s) Camry (V20), Celica (T160/T180).

Used in sequential injection setups on late-generation 3S-FE engines. Fuel Pump Control

Use automotive-grade wire labels or heat-shrink label tubes on your harness to identify +B , IGSW , FC , and grounds for seamless maintenance down the line.