Idle Control System

Idle Control System

When the engine is cold, the A/C compressor is on, the transmission is in gear, or the brake pedal is pressed, the ECM controls current to the IAC valve to maintain the correct idle speed. Refer to the System Diagram to see the functional layout of the system.

Brake pedal position Switch

The brake pedal position switch signals the ECM when the brake pedal is pressed.

Clutch pedal position Switch

The clutch pedal position switch signals the ECM when the clutch pedal is pressed.

Engine start Switch

The engine start switch signals the ECM when the engine is cranking.

IAC (Idle Air Control) Valve




To maintain the proper idle speed, the IAC valve changes the amount of air bypassing the throttle body in response to an electrical signal from the ECM.

Neutral Position Switch

The neutral position switch signals the ECM when the transmission is shifted out of neutral.

Reverse Position Switch

The reverse position switch signals the ECM when the transmission is shifted into reverse.