Circuit Description

The rotary solenoid type idle speed control (ISC) valve is located under the throttle body and intake air bypassing the throttle valve flows to the idle speed control (ISC) valve through the passage.

In this way the intake air volume bypassing the throttle valve is regulated, controls the engine speed.

The ECM operates the idle speed control (ISC) valve only to perform idle-up and provide feedback for the target idling speed.

Fig 1: Idle Air Control System Circuit Description

CIRCUIT DESCRIPTION

DTC No.	DTC Detecting Condition	Trouble Area
P0505	Idle Speed Continues To Vary Greatly From Target Speed	Open Or Short In Idle Speed Control (ISC) Valve Circuit Idle Speed Control (ISC) Valve Is Stuck Or Closed ECM Air Induction System PCV Valve And Hose
P0511	Open Or Short ISC Circuit