Idle Control System

Idle Control System

The idle speed of the engine is controlled by the idle air control (IAC) valve:

- After the engine starts, the IAC valve opens for a certain amount of time. The amount of air is increased to raise the idle speed.
- When the engine coolant temperature is low, the AC valve is opened to obtain the proper fast idle speed. The amount of bypassed air is controlled in relation to engine coolant temperature.

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.

A/T Gear Position Switch (CVT)
The A/T gear position switch signals the ECM when the transmission is in N or P position.

Brake Pedal Position Switch
The brake pedal position switch signals the ECM when the brake pedal is pressed.

Clutch Interlock Switch (M/T)
The clutch interlock switch signals the ECM when the clutch pedal is pressed.




Idle Air Control (IAC) 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.

Idle Stop Switch (CVT)
The idle stop switch signals the ECM when the brake pedal is pressed.

Neutral Position Switch (M/T)
The neutral position switch signals the ECM when the transmission is shifted out of neutral.

Back-up Light Switch (M/T)
The back-up light switch signals the ECM when the transmission is shifted into reverse.