The ISCA (Idle Speed Control Actuator) is designed to maintain a steady desired idle speed. Idle airflow is adjustedthrough the idle air actuator in order to maintain the desired idle speed under various load conditions. Load conditions vary due to numerous factors, such as engine temperature, air conditioning, electrical load and power steering load.
If actual engine speed is more than 200 RPM higher than desired engine speed, P0507 is set.
Item | Detecting Condition | Possible Cause | |
DTC Strategy | ● Rationality check, high | ● Poor connection ● Leak in intake air system ● Carbon pile ● ISCA | |
General Enable Conditions | ● Vehicle speed = 0 ● Coolant temperature > 70℃ ● Intake air temperature > -6℃ ● Altitude < 3000m ● Idle status ● No error on the related sensors. (VSS,ECTS,IATS,etc) ● Idle speed control torque > 14.84% ● Engine load < 35% ● No error on the PCV ● Monitoring of VSS is ended | ||
Case 1 | Enable Conditions | ● Idle speed control torque ≤ -15% ● Idle speed controller control duty ≤ 18% | |
Threshold Value | ● Desired engine speed - Engine speed 〈 -200rpm | ||
Case 2 | Threshold Value | ● Fuel cut-off ≥ 3times | |
Diagnostic Time | ● 15 sec | ||
MIL ON Condition | ● 2 driving cycle |
Temperature [℃(℉)] | Closing Coil Resistance (Ω) | Opening Coil Resistance (Ω) |
20 (68) | 14.6 ~ 16.2 | 11.1 ~ 12.7 |
Connect scantool to Data Link Connector(DLC).
IG "ON".
Select "Diagnostic Trouble Codes(DTCs)" mode, and then Press F4(DTAL) to check DTC'sinformation from the DTCs menu
Confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditionsnoted in the freeze frame data or enable conditions noted in the DTC detecting condition.
Read "DTC Status" parameter.
Is parameter displayed "History(Not Present) fault"?
History fault : DTC occurred but has been cleared.
Present fault : DTC is occurring at present time.
▶ Fault is intermittent caused by poor contact in the sensor’s and/or ECM’s connector or wasrepaired and ECM memory was not cleared. Thoroughly check connectors for looseness,poor connection, bending, corrosion, contamination, deterioration, or damage.Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.
▶ Go to "Terminal & Connector Inspection" procedure
Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
Has a problem been found?
▶ Repair as necessary and go to "Verification of vehicle Repair" procedure.
▶ Go to "Power circuit inspection" procedure.
Key "OFF".
Disconnect ISCA connector.
Key "ON".
Measure the voltage between terminal 2 of ISCA harness connector and chassis ground.
Specification : B+
Is the measured voltage within specification?
▶ Go to "Control circuit inspection" procedure.
▶ Repair Open or Short in power circuit and then, go to "Verification of Vehicle Repair" procedure.
Key "OFF".
Disconnect ISCA connector and Key "ON".
Measure the voltage between terminal 1 of ISCA harness connector and chassis ground.
Measure the voltage between terminal 3 of ISCA harness connector and chassis ground.
Specification : 1.3~1.7 V (at terminal 1), Approx 1.7~2.1V (at terminal 3)
Is the measured voltage within specification?
▶ Go to "System inspection" procedure.
▶ Repair Open or Short in control circuit and then, go to "Verification of Vehicle Repair" procedure.
Visual inspection.
Key "OFF".
Check intake air system
▶ Check assembling state and damage on throttle body gasket.
▶ Check assembling/sealing state and damage on MAFS and PCV valve.
Is everything O.K?
▶ Go to "Component inspection" procedure.
▶ Repair as necessary and then, go to "Verification of Vehicle Repair" procedure.
ISCA visual check.
Key "OFF".
Disassemble ISCA.
Check contamination, damage or stuck on ISCA.
Check the operating sound when key turns "OFF" to "ON".
Is ISCA O.K?
▶ Go to "ISCA check" procedure.
▶ Substitute with a known - good ISCA and check for proper operation.
▶ If the problem is corrected, replace ISCA and go to "Verification of Vehicle Repair" procedure.
ISCA check.
Key "OFF".
Disassemble ISCA.
Measure the resistance between terminal 1 and 2 of ISCA harness connector. (Component side)
Measure the resistance between terminal 2 and 3 of ISCA harness connector. (Component side)
Temperature [℃(℉)] | Closing Coil Resistance (Ω) | Opening Coil Resistance (Ω) |
20 (68) | 14.6 ~ 16.2 | 11.1 ~ 12.7 |
Is the measured resistance within specifications?
▶ Many malfunctions in the electrical system are caused by poor harness(es) and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage. So, check poor connections and the related circuit between ECM and component thoroughly. Repair as necessary and go to "Verification of Vehicle Repair" procedure.
▶ Substitute with a known - good ISCA and check for proper operation.
▶ If the problem is corrected, replace ISCA and go to "Verification of Vehicle Repair" procedure.
After a repair, it is essential to verify that the fault has been corrected.
Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode.
Press F4(DTAL) and confirm that "DTC Readiness Flag" indicates "Complete".
If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions.
Read "DTC Status" parameter.
Is parameter displayed "History(Not Present) fault"?
▶ System performing to specification at this time. Clear the DTC.
▶ Go to the applicable troubleshooting procedure.