P1505
DTC P1505 IDLE CHARGE ACTUATOR SIGNAL LOW OF COIL #1Component Location:
GENERAL DESCRIPTION
The Idle Speed Control Actuator(ISCA) valve 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"?
- History (Not Present) fault DTC occurred but has been cleared.
- Present fault DTC is occurring at present time.
YES: 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 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.
COMPONENT INSPECTION
1. Ignition "OFF".
2. Disconnect ISCA connector
3. Measure resistance between terminals 1 and 2 of the ISCA connector(Component side)
Specification: 14.9 - 16.1Ohm at 20 degrees C (68 degrees F)
4. Is resistance within the specification?
YES: Go to next step as below.
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
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 "OFF".
2. Disconnect ISCA connector.
3. Ignition "ON" & "OFF".
4. Measure voltage between terminal 2 of the ISCA harness connector and chassis ground.
Specification: Approx. B+
5. Ignition "OFF"
6. Disconnect ECM connectors
7. Ignition "ON" & Engine "OFF"
8. Measure voltage between terminal 9 of the ECM harness connector(C133-1) and chassis ground
Specification: Approx. B+
9. Is voltage display near the specified value?
YES: With ignition "OFF", reconnect the ECM connectors. Then go to next step as below.
NO: Check for an open or short to ground in the power supply circuit. Repair as necessary and go to "Verification of Vehicle Repair" procedure
SIGNAL CIRCUIT INSPECTION
1. Ignition "ON" & Engine "OFF".
2. Measure voltage between terminal 1 of the ISCA harness connector and chassis ground
Specification: Approx. 3-4V
3. Is voltage within the specification?
YES: 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 next step as below.
4. Check for open in signal harness
1. Ignition "OFF".
2. Measure resistance between terminals 1 of the ISCA harness connector and 46 of the ECM harness connector
Specification: Approx 0 Ohm
3. Is resistance within the specification?
YES: Go to next step as below.
NO: Repair as necessary and go to "Verification of Vehicle Repair" procedure.
5. Check for short to ground in signal harness.
1. Ignition "OFF".
2. Measure resistance between terminal 1 of the ISCA harness connector and chassis ground
Specification: Infinite
3. Is resistance within the specification?
YES: 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.
NO: Repair open or short in harness 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: System performing to specification at this time. Clear the DTC.
NO: Go to the applicable troubleshooting procedure.