IAC Valve Position Sensor

Operation

The IAC valve position sensor converts the changes (increase or decrease) in the valve position of the idle air control motor into pulse signals and inputs these signals to the engine control module. The engine control module determines the valve position from these signals and also controls the idle air control motor.

5V power is supplied to the IAC valve position sensor from the engine control module, and the ground connection is positioned in the engine control module.

5V power is applied to the two IAC valve position sensor output terminals from the engine control module. When the IAC valve position is changed (increased or decreased) by the DC motor inside the idle air control motor, the IAC valve position sensor generates a pulse signal from the opening and closing between the output terminal and the ground.

Troubleshooting

Hint 1: The IAC valve position sensor is the most important sensor for controlling the idle speed. If a malfunction develops when the engine is idling and the engine load is varied by turning the air conditioning switch to ON and OFF, etc., this sensor is probably defective.





Inspection








Harness Inspection


Caution: When shifting the selector lever to the D range, apply brake to prevent the vehicle from moving forward.