Idle Speed/Throttle Actuator - Electronic: Testing and Inspection

IAC Operation:

- The rotary solenoid type IAC valve is provided on the intake air chamber and intake air bypassing the throttle valve is directed to the IAC valve through a passage.

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

- The ECM operated only the AC valve to perform idle-up and provide feedback for the target idling speed, but in the 4A-FE engine of the Corolla, a VSV for idle-up control is also added (for air conditioning).

Diagnostic Chart:

Diagnostic Chart

Circuit Diagram:

Circuit Diagram

Inspection Procedure; Step 1:

Inspection Procedure; Step 1

Inspection Procedure; Step 2 - 3:

Inspection Procedure; Step 2 - 3