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.
ECM sets DTC P1505 if the ECM detects that the IAC(OPEN) control line is open or short to ground.
Item
Detecting Condition
Possible Cause
DTC Strategy
? Driver stage check
? Open or short to ground in harness
? Contact resistance in connectors
? Defective IAC valve
Enable Conditions
? Battery voltage >10V
Threshold Value
? Short to ground or line break
Diagnostic Time
? 1 sec.
Fail Safe
? ECM controls idle speed with predetermined value
Specification
Opening Coil
Closing Coil
14.5~16.5O
16.6~18.6O