Idle Control System

When the engine is cold, the A/C compressor is on, the transmission is in gear, the brake pedal is depressed, the P/S load is high, or the alternator is charging, the PCM controls current to the A/C valve to maintain the correct idle speed.




The idle speed of the engine is controlled by the IAC (Idle Air Control) valve:
- After the engine starts the IAC valve opens for a certain time. The amount of air is increased to raise the idle speed by about 150 - 300 rpm.
- When the engine coolant temperature is low, the IAC valve is opened to obtain the proper fast idle speed. The amount of bypassed air is thus controlled in relation to engine coolant temperature.