DTC P0505 Idle Control System Malfunction; DTC P0511 Idle Air Control Circuit: Description

WARNING: This page is about a different variant/trim than selected.

Fig 1: Idle Air Control (IAC) Valve Air Flow Diagram

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

The Idle Air Control (IAC) valve, of a rotary solenoid type, is located under the throttle body. Intake air, bypassing the throttle valve, flows into the IAC valve through a passage.

The valve regulates the volume of intake air that bypasses the throttle valve and allows the engine idling speed to be controlled.

The IAC valve is used by the ECM to perform idle-up and its feedback signal is used as one factor in target engine idling speed regulation.

DTC TROUBLE DETECTION REFERENCE

DTC No.	DTC Detection Condition	Trouble Area
P0505	Engine idling speed continues to vary greatly from target idling speed	Open or short in IAC valve circuit IAC valve stuck or closed A/C switch circuit Air induction system PCV valve and hose ECM
P0511	Open or short in IAC valve circuit	Open or short in IAC valve circuit IAC valve stuck or closed A/C switch circuit ECM