P1505

P1505

Component Location:

General Description
The Idle Speed Control Actuator (ISCA) 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 ISCA valve is to maintain idle speed according to various engine loads and conditions, and also to provide additional air during starting. The ISCA 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.

DTC Description
ECM sets DTC P1505 if the ECM detects that the ISCA (OPEN) control circuit is open or short to ground.

DTC Detecting Condition:

Specification:

Schematic Diagram:

Signal Waveform:

Monitor DTC Status
1. Connect scan tool and select "Diagnostic Trouble Codes (DTCs)" mode
2. Press F4(DTAL) to select DTC information from the DTCs menu.
3. Confirm that "DTC Readiness Flag" indicates "Complete". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions
4. Read "DTC Status" parameter






5. Is parameter displayed "History (Not Present) fault"?

CAUTION:
- History (Not Present) fault : DTC occurred but has been cleared.
- Present fault : DTC is occurring at present time.

YES
a. 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 then go to "Verification of Vehicle Repair" procedure

NO
a. Go to next step as below.

Component Inspection
1. Ignition "OFF"
2. Disconnect ISCA valve connector
3. Measure resistance between terminals 1 and 2 of the valve connector (Component side)

Specification






4. Is resistance within the specification?

YES
a. Go to next step as below

NO
a. Check ISCA for contamination, deterioration, or damage. Substitute with a known-good ISCA and check for proper operation. If the problem is corrected, replace ISCA and then go to "Verification of Vehicle Repair" procedure

Power Supply Circuit Inspection
1. Ignition "ON" & Engine "OFF"
2. Measure voltage between terminal 2 of the valve harness connector and chassis ground

Specification : Approx. B+






3. Is voltage within the Specification?

YES
a. Go to next step as below

NO
a. Check for an open or short to ground in the power supply circuit between the ISCA valve and main relay. Repair as necessary and go to "Verification of Vehicle Repair" procedure

Signal Circuit Inspection
1. Measure voltage between terminal 1 of the valve harness connector and chassis ground

Specification : Approx. 2 - 4 V






2. Is voltage within the Specification?

YES
a. Go to next step as below

NO
a. Repair as necessary and go to "Verification of Vehicle Repair" procedure

Terminal and Connector Inspection
1. 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.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?

YES
a. Repair as necessary and go to "Verification of Vehicle Repair" procedure

NO
a. Thoroughly check for poor connection between ECM and component: backed out terminal, improper mating, broken locks or poor terminal to wire connection. Repair as necessary and go to "Verification of Vehicle Repair" procedure

Verification of Vehicle Repair
After a repair, it is essential to verify that the fault has been corrected.
1. Connect scan tool and select "Diagnostic Trouble Codes (DTCs)" mode
2. 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.
3. Read "DTC Status" parameter
4. Is parameter displayed "History (Not Present) fault"?

YES
a. System performing to specification at this time. Clear the DTC

NO
a. Go to the applicable troubleshooting procedure.