P1507
Fuel System - Troubleshooting - P1507Component Location:
GENERAL DESCRIPTION
The 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 PCM controls both coils by grounding their control circuits. According to the control signals from the PCM, the valve rotor rotates to control the by pass airflow into the engine.
DTC DESCRIPTION
PCM sets DTC P1507 if the PCM detects that the ISCA(CLOSE) control line is open or short to ground.
DTC Detecting Condition:
MONITOR DTC STATUS
1. Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode.
2. Press F5(INFO) 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"?
NOTE:
1. History (Not Present) fault : DTC occurred but has been cleared.
2. Present fault : DTC is occurring at present time.
YES - Fault is intermittent caused by poor contact in the sensor's and/or PCM's connector or was repaired and PCM memory was not cleared. Thoroughly check connectors for loose or poor connections, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.
NO - Go to "Component Inspection" 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 - Repair as necessary and go to "Verification of Vehicle Repair" procedure.
NO - Go to "Power Supply Circuit Inspection" 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 - Go to "Signal Circuit Inspection" procedure.
NO - Check for an open or short to ground in the power supply circuit between the ISCA and main relay. Repair as necessary and go to "Verification of Vehicle Repair" procedure.
SIGNAL CIRCUIT INSPECTION
1. Check for open in signal harness.
1. Ignition "OFF".
2. Disconnect PCM connector.
3. Measure resistance between terminals 3 of the valve harness connector and 78 of the PCM harness connector.
Specification : Approx. 0 Ohm
4. Is resistance within the specification?
YES - Go to next step.
NO - Repair as necessary and go to "Verification of Vehicle Repair" procedure.
2. Check for short to ground in signal harness.
1. Measure resistance between terminal 3 of valve harness connector and chassis ground.
Specification : Infinite
2. Is resistance within the specification?
YES - Check for poor connection between PCM 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.
NO - Repair open or short in harness and go to "Verification of Vehicle Repair" procedure.
Specification:
COMPONENT INSPECTION
1. Ignition "OFF".
2. Disconnect ISCA connector.
3. Measure resistance between terminals 2 and 3 of the valve connector(Component side)
4. Is resistance within the specification?
YES - Go to next step.
NO - 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.
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 F5(INFO) 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 - System performing to specification at this time. Clear the DTC
NO - Go to the applicable troubleshooting procedure.
Schematic Diagram:
