Circuit Description
WARNING: This page is about a different car, the 2003 Lexus RX 300. However, it is still accessible from the selected car via links, so may be relevant.
Idle Air Control (IAC) valve is a rotary solenoid type and is located in front of air intake chamber. Intake air by-passing throttle valve is directed to IAC valve through a passage. This allows air volume by-passing throttle valve to be regulated. See Fig 1. DTC P0505/P0511 is set if idle speed continues to vary greatly from target speed. Possible causes are:
- IAC valve stuck or closed.
- Open or short in IAC valve circuit.
- Open or short in A/C signal circuit.
- Faulty air intake hose.
- Faulty ECM.
- PCV piping.