The Idle Speed Control Actuator (ISCA) is installed on the intake manifold and controls the intake airflow that is by-passed around the throttle plate to keep constant engine speed when the throttle valve is closed. The function of the ISCA is to maintain idle speed according to various engine loads and conditions, and also to provide additional air during starting. The ISCA 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 P1506 if the ECM detects that the ISCA control line is short to battery line.
Item
Detecting Condition
Possible cause
Monitoring Strategy
? Circuit continuty check (opening coil)
? Short to battery in control circuit
? Faulty ISCA
? Faulty ECM
Threshold value
? Shorted to battery voltage
Fail safe astion
? Shorted circuit
Diagnostic Time
Fail Safe
? The limp home value of ISCA depends on engine speed and throttle angle.
- ECM controls with mapping data..
Idle
Normal Parameter
Open Coil
Closing Coil
Resistance
10 ~ 12.5 ?
10.5 ~ 14 ?
Hi-scan Data display
A/CON switch OFF
25 ~ 45 %
A/CON switch ON
35 ~ 55 %
Using the channel 1,2 of scan tool,it is the waveform at terminal 1,3 of ISCA in idling
The wave must be opposite to each other.
The lower voltage must be below 1V and the upper must be battery voltage.