P1506
DTC P1506 IDLE CHARGE ACTUATOR SIGNAL HIGH OF COIL #1Component Location:
GENERAL DESCRIPTION
The Idle Speed Control Actuator (ISCA) is installed on the intake manifold and controls the intake airflow that is by-passed around the throttle plate to keep constant engine speed when the throttle valve is closed. The function of the ISCA is to maintain idle speed according to various engine loads and conditions, and also to provide additional air during starting. The ISCA 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 P1506 if the PCM detects that the ISCA control line is short to battery line
DTC Detecting Condition:
Specification:
Schematic Diagram:
SIGNAL WAVEFORM & DATA
Using the channel 1, 2 of scan tool, it is the wave form at terminal 1, 3 of ISCA in idling
1. The wave must be opposite to each other.
2. The lower voltage must be below 1 V and the upper must be battery voltage.
The above waveforms are the voltage signals generated when ISCA operates. This ISCA type is duty type and the time ratio opened determines duty amount. The left side is the waveform of ISCA Opening coil during idle. The right side is the waveform of ISCA Closing coil during idle.
MONITOR DTC STATUS
This is the inspection procedure to determine whether it is present DTC or memoried one by monitoring the current signal or by using the function of oscilloscope with Hi-scan pro.
1. Connect scantool to Data Link Connector(DLC).
2. Warm up the engine to normal operating temperature.
3. Monitor the "ISCA signal" parameter on the scantool.
NOTE: The data shown above is only for reference and there may be a little difference actually.
Service standard
A/CON switch OFF: 25 - 45%
A/CON switch ON: 35 - 55%
4. Is parameter displayed within specifications?
YES: Fault is intermittent caused by poor contact in the sensor's and/or PCM's connectors or was regained and PCM memory was not cleared.Thoroughly check connectors for looseness, poor connection, bending, contamination, deterioration, or damage. Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.
NO: Go to "W/Harness Inspection" procedure
TERMINAL & CONNECTOR INSPECTION
1. 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.
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 "Control circuit inspection" procedure.
CONTROL CIRCUIT INSPECTION
1. Check for short between power and control harness
1. Ignition "OFF"
2. Disconnect ISCA sensor connector.
3. Ignition "ON" & Engine "OFF"
4. Measure voltage between terminal 3 of sensor ha mess connector and chassis ground.
Specification : approximately 3.6 V
5. Is measure voltage within Specification?
YES: Go to "Component Inspection" procedure.
NO:
- Check for short to battery in control harness.
- Repair as necessary and then go to Verification of Vehicle Repair" procedure.
NOTE: In case,when the ISCA connector is disconnected, the voltage of ISCA terminal 3 is 12 V.
- Possible cause: Short circuit in battery power line after fuse (ISA INJ).
COMPONENT INSPECTION
The purpose of measuring ISCA resistance is to find if the open circuit is in the component.
1. Check ISCA
1. Measure resistance between terminal 2 and 3 of sensor connector(TO sensor side)
Specifications: 20 °C (68 °F) :14.9 - 16.1 Ohms
2. Is measure resistance within Specification?
YES: Substitute with a known-good PCM and check for proper operation. If the problem is corrected, replace PCM and then go to "Verification of Vehicle Repair" procedure.
NO: 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. Monitor and record the Freeze Frame Data for the Diagnostic Trouble Code (DTC) which has been diagnosed.
2. Using a Scantool, Clear the DTCs.
3. Operate the vehicle within conditions noted in the freeze frame data or enable conditions.
4. Monitor that all rediness test have been verified as "Complete"
5. Are any DTCs present?
YES: Go to the applicable troubleshooting procedure.
NO: System is performing to specification at this time.