Idle Air Control Systems

The Idle Air Control (IAC) system is used to stabilize idle speed during cold engine and after warm-up operations. Idle speed stabilization is needed due to the effect engine load changes has on emission output, idle quality and vehicle driveability. The IAC system uses an ECM controlled idle air control valve (IACV) that regulates the volume of air bypassed around the closed throttle. The ECM controls the IACV by applying various input signals against an IAC program stored in memory.

There are four different types of IACVs used on Toyota models. These systems are referred to as:

• Duty-Control Rotary Solenoid

• Duty-Control Air Control Valve (ACV)

• On/Off Vacuum Switching Valve (VSV)

Do It Yourself Car Diagnosis

Do It Yourself Car Diagnosis

Don't pay hundreds of dollars to find out what is wrong with your car. This book is dedicated to helping the do it yourself home and independent technician understand and use OBD-II technology to diagnose and repair their own vehicles.

Get My Free Ebook


Post a comment