2.
Probe(+) : ISCA harness connector NO3.
Probe(-) : Chassis ground.
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.
The 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 | ● Signal check High | ● Short between power and control line |
Threshold value | ● Short to battery ● Air passage : 0% | |
Enable Conditions | ● Action power stage(closing) : OFF ● Air passage : Limp home | |
Diagnostic Time | ||
MIL on condition |
Service standard
A/CON switch OFF : 25~45%
A/CON switch ON : 35~55%
Start engine and warm up to operating temperature.
Probe(+) : ISCA harness connector NO3.
Probe(-) : Chassis ground.
Service standard
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.
If the waveform changes as TPS changes or as A/CON switch on and off,it is normal.
In case there is no symptom and wrong data but DTC is shown
The problem may be intermittent so slightly shake the connector and harness vertically and horizontally to check if there is any data changes
If the data changes normally, the problem was intermittent so erase DTC and verify the same DTC reoccure.
Go to "Terminal and Connector inspection" procedure.
In case there is symptom and wrong data with DTC
Check open,short or connector’s connection for ISCA.
Check the deterioration of ISCA performance.
Go to "Signal circuit inspection" procedure.
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.
