Idle Speed Control System (ES300 & RX300)
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2002 Lexus SC 430, 2002 Lexus RX 300, 2002 Lexus LX 470, 2002 Lexus LS 430, and 2002 Lexus IS 300. However, it is still accessible from the selected car via links, so may be relevant.
Engine Control Module (ECM) is programmed with engine idle speed values. Idle speed control system provides a stable idle speed when engine is cold or idle speed decreases due to electrical load etc. ECM uses various input signals to maintain proper idle speed by controlling Idle Air Control (IAC) valve. IAC valve is located under No. 1 throttle body.