P0748
COMPONENT LOCATION
GENERAL DESCRIPTION
Variable Faced Solenoid (Linear Solenoid) : With the duty control which uses higher frequency(600Hz), instead of the existing PWM type which adapts low frequency(60Hz) to control, spool valve can be controlled precisely.
In PWM control, the amount of oil flow is determined by the duration of "ON"signal among continuously repeated ON/OFF signals.
In VFS, the amount is decided by how widely spool valve open the passage of going through.
DTC DESCRIPTION
The TCM checks the VFS Control Signal by monitoring the feedback signal from the solenoid valve drive circuit. If an unexpected signal is monitored (for example, high voltage is detected when low voltage is expected, or low voltage is detected when high voltage is expected), the TCM judges that the Low and Reverse control solenoid circuit is malfunctioning and sets this code.
DTC DETECTING CONDITION
MONITOR SCANTOOL DATA
1. Connect scantool to data link connector(DLC).
2. Engine "ON".
3. Monitor the "PRESS CONTROL SOL. VALVE" parameter on the scantool.
4. Shift gear at each position.
5. Is "PRESS CONTROL SOL DUTY " follow the reference data?
YES
> Fault is intermittent caused by poor contact in the sensor's and/or TCM(PCM)'s connector or was repaired and TCM(PCM) 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.
NO
> Go to "Terminal&connector 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 then go to "Verification of vehicle repair" procedure.
NO
> Go to "Power supply circuit inspection" procedure.
POWER SUPPLY CIRCUIT INSPECTION
1. Disconnect "A/T SOLENOID VALVE" connector.
2. Measure voltage between terminal "8" of the sensor harness connector and chassis ground.
3. Measure voltage of VFS solenoid valve.
Specification: Approx.12V
4. Is voltage within specifications?
YES
> Go to "Signal circuit inspection" procedure.
NO
> Check that A/T-20A fuse in engine room junction is installed or not blown.
> Check for open in harness. Repair as necessary and go to "Verification of vehicle repair" procedure.
SIGNAL CIRCUIT INSPECTION
1. Check signal circuit open inspection.
(1) Ignition "OFF".
(2) Disconnect "A/T SOLENOID VALVE" connector and "PCM/TCM" connector.
(3) [2.4L]
Measure resistance between terminal "8" of the ATM SOLENOID VALVE harness connector and terminal "19" of the TCM(PCM) harness connector.
[2.7L]
Measure resistance between terminal "7" of the ATM SOLENOID VALVE harness connector and terminal "75" of the PCM/TCM harness connector.
Specification: approx. 0 Ohms
(4) Is resistance within specifications?
YES
> Go to "Check signal circuit short inspection" procedure.
NO
> Check for open in harness. Repair as necessary and go to "Verification of vehicle repair" procedure.
2. Check signal circuit short inspection
(1) Ignition "OFF".
(2) Disconnect "A/T SOLENOID VALVE" connector and "PCM/TCM" connector
(3) Measure resistance between terminal "7" of the ATM SOLENOID VALVE harness and chassis ground.
Specification: Infinite
(4) Is resistance within specifications?
YES
> Go to "Component inspection" procedure.
NO
> Check for short to ground in harness. Repair as necessary and go to "Verification of vehicle repair" procedure.
COMPONENT INSPECTION
1. CHECK SOLENOID VALVE
(1) Ignition "OFF".
(2) Disconnect "A/T SOLENOID VALVE" connector.
(3) Measure resistance between terminal "7" and terminal "8" of the ATM SOLENOID VALVE harness connector.
Specification: Approximately 4.35±0.35Ohms [20°C(68°F)]
(4) Is resistance within specification?
YES
> Go to "CHECK PCM/TCM" as below.
NO
> Replace "PRESS CONTROL SOL VALVE(VFS)" as necessary and go to "Verification of vehicle repair" procedure.
2. CHECK PCM/TCM
(1) Connect scantool to data link connector(DLC).
(2) Ignition "ON" & Engine "OFF".
(3) Select A/T Solenoid valve Actuator test and Operate Actuator test.
(4) Can you hear operating sound for "PRESS CONTROL SOL VALVE(VFS)" Actuator testing function?
YES
> Go to "Verification of vehicle repair" procedure.
NO
> Replace PCM/TCM as necessary and go to "Verification of vehicle repair" procedure.
ACTUATOR TEST CONDITION
a. IG SWITCH ON
b. TRANSAXLE RANGE SWITCH is normal
c. P RANGE
d. Vehicle Speed 0mph(0km/h)
e. Throttle position sensor< 1V
f. IDLE SWITCH ON
g. ENGINE RPM 0
VERIFICATION OF VEHICLE REPAIR
After a repair, it is essential to verify that the fault has been corrected.
1. Connect scantool and select "Diagnostic Trouble Codes(DTCs)" mode.
2. Using a scantool, Clear DTC.
3. Operate the vehicle within DTC Enable conditions in General information.
4. Are any DTCs present?
YES
> Go to the applicable troubleshooting procedure.
NO
> System performing to specification at this time.
SIGNAL WAVEFORM
SPECIFICATION
Solenoid Valve for Pressure Control
a. Sensor type : Normal open 3-way
b. Operating temperature : -22-266°F(-30°C~130°C)
c. Frequency :
a. LR, 2ND, UD, OD, RED : 61.27Hz (at the ATF temp. -20°C above)
b. DCC : 30.64Hz
c. VFS : 600 ± 20Hz
** KM series : 35Hz
d. Internal resistance :
a. 2.7-3.4Ohms(68°F or 20°C) - LR, 2ND, UD, OD, RED, DCC
b. 4.35±0.35Ohms(68°F or 20°C) - VFS
e. Surge voltage : 56 V(except VFS)