P0743

DTC P0743





GENERAL DESCRIPTION
The PCM controls the locking and unlocking of the Torque Converter Clutch ( or Damper Clutch ), to the input shaft of the transmission, by applying hydraulic pressure. The main purpose of T/C clutch control is to save fuel by decreasing the hydraulic load inside the T/C. The PCM outputs duty pulses to control the Damper Clutch Control Solenoid Valve (DCCSV) and hydraulic pressure is applied to the DC according to the DCC duty ratio value. When the duty ratio is high, high pressure is applied and the Damper Clutch is locked. The normal operating range of the Damper Clutch Control duty ratio value is from 30% (unlocked) to 85% (locked).

DTC DESCRIPTION
The PCM checks the Damper Clutch 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 PCM judges that DCCSV circuit is malfunctioning and sets this code.

DTC DETECTING CONDITION:

SCHEMATIC DIAGRAM:

SIGNAL WAVEFORM:

MONITOR SCANTOOL DATA
1. Connect Scantool to data link connector (DLC).
2. Engine "ON".
3. Monitor the "TCC SOL. VALVE" parameter on the Scantool.
4. Select "D RANGE" and operate the vehicle.
5. Check "TCC SOL. VALVE" parameter value changes while driving.





6. Does "TCC SOLENOID DUTY " follow the reference data?
YES
^ Fault is intermittent caused by poor contact in the sensors and/or PCM's connector or was repaired and 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 "Signal circuit inspection" procedure.

SIGNAL CIRCUIT INSPECTION
1. Disconnect "A/T SOLENOID VALVE" connector.
2. IGNITION "ON", ENGINE "OFF".
3. Measure voltage between terminal "1" of the sensor harness connector and chassis ground.
Specification: approximately 6V





4. Is resistance within specifications?
YES
^ Go to "Component inspection" procedure.
NO
^ Check for open or short in harness. Repair as necessary and Go to "Verification of vehicle repair" procedure. L If signal circuit in harness is OK, Go to "Check PCM" of the "Component inspection" procedure

COMPONENT INSPECTION
1. CHECK SOLENOID VALVE
A. Ignition "OFF".
B. Disconnect "NT SOLENOID VALVE" connector.
C. Measure resistance between terminal "1" and chassis ground.
Specification: Approximately 2.7-3.4 Ohms [20°C (68°F)]





D. Is resistance within specification?
YES
^ Go to "CHECK PCM" as below.
NO
^ Replace TCC SOLENOID VALVE as necessary and go to "Verification of vehicle repair" procedure.

2. CHECK PCM
A. Connect Scantool to data link connector (DLC).
B. Ignition "ON" & Engine "OFF".
C. Select A/T solenoid valve actuator test and operate actuator test.
D. Can you hear operating sound for TCC SOLENOID VALVE actuator testing function?
YES
^ Go to "Verification of vehicle repair" procedure.
NO
^ Replace TCM (PCM) as necessary and Go to "Verification of vehicle repair" procedure ACTUATOR TEST CONDITION
1. IG SWITCH ON
2. TRANSAXLE RANGE SWITCH is normal
3. P RANGE
4. Vehicle speed 0 mph (0 km/h)
5. Throttle position sensor 1V
6. IDLE SWITCH ON
7. ENGINE RPM 0

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. 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.