3.
Monitor the "ISCA" parameters on the scantool.
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 there is Short to power in ISCA(opening coil) circuit, PCM sets DTC P1506.
Item | Detecting Condition | Possible Cause |
DTC Strategy | ● Circuit continuity check, high (opening coil) | ● Poor connection ● Short to power in control circuit ● ISCA ● ECM |
Enable Conditions | ||
Threshold Value | ● Shorted to battery voltage | |
Diagnostic Time | ● Continuous | |
MIL | ● ON |
Connect scantool to Data Link Connector(DLC).
Warm up the engine to normal operating temperature.
Monitor the "ISCA" parameters on the scantool.
Are the parameters displayed correctly?
▶ Fault is intermittent caused by poor contact in the sensor’s and/or ECM’s connector or was repaired 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 go to "Verification of vehicle Repair" procedure.
▶ Go to "Terminal and 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 "Control circuit inspection" procedure.
Key "OFF".
Disconnect ISCA connector.
Key "ON"＆ ENG "OFF".
Measure the voltage between terminal 3 of ISCA harness connector and chassis ground.
Specification : Approx 2V
Is the measured voltage within specification?
▶ Go to "Component inspection" procedure.
▶ Repair Short to power in control circuit 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) |
20~35 (68~95℉) | 15.4±0.8 | 11.9±0.8 |
Is the measured resistance within specifications?
▶ Substitute with a known - good ECM and check for proper operation.
▶ If the problem is corrected, replace ECM 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.
Clear the DTCs and Operate the vehicle within DTC Enable conditions in General information.
Are any DTCs present ?
▶ Go to the applicable troubleshooting procedure.
▶ System is performing to specification at this time.
