: IGT1–4 for ignition coil signals and IGF for the ignitor feedback signal.

: Traces power flow through the EFI and AM2 fuses to the starter relay and generator assembly.

: #10 , #20 , #30 , and #40 representing individual fuel injector outputs.

The overall electrical wiring guide for the Vios links several critical systems to the ECU:

Understanding the is vital for diagnosing electrical faults, installing aftermarket controllers, or performing engine remapping. The Engine Control Unit (ECU) acts as the "brain," managing fuel delivery, ignition timing, and emission controls based on input from various sensors. Core Components & Pinouts

: THW (Coolant Temp), THA (Intake Air Temp), VTA (Throttle Position), and OX (Oxygen Sensor). Typical Wiring Connections

A Vios ECU typically uses multi-pin plugs (commonly 4-plug or 5-plug configurations) to connect with the engine harness. Key terminal abbreviations often found in these diagrams include: