Component Location
Description
1. General Description

The Idle Air Control(IAC) valve is installed on the intake manifold and controls the intake airflow that is bypassed around the throttle plate to keep constant engine speed when the throttle valve is closed. The function of the IAC valve is to maintain idle speed according to various engine loads and conditions, and also to provide additional air during starting. The IAC valve consists of an opening coil, a closing coil, and a permanent magnet. Based on information from various sensors, the ECM controls both coils by grounding their control circuits. According to the control signals from the ECM, the valve rotor rotates to control the by pass airflow into the engine.

2. DTC Description

ECM sets DTC P1508 if the ECM detects that the IAC(CLOSE) control line is short to battery.

DTC Detecting Condition

Item

Detecting Condition

Possible Cause

DTC Strategy

● Driver stage check

● Short to battery in harness

● Contact resistance in connectors

● Defective IAC valve

Enable Conditions

● Battery voltage >10V

Threshold Value

● Short to battery

Diagnostic Time

● 1 sec.

Fail Safe

● ECM controls idle speed with predetermined value

Specification

Specification

Opening Coil

Closing Coil

14.5~16.5Ω

16.6~18.6Ω

Schematic Diagram
note
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Signal Waveform
Яндекс.Метрика