P0744

P0744 A/T TCC S/V FUNCTION (LOCK -UP)





Description
This malfunction is detected when the torque converter clutch does not lock-up as instructed by the TCM. This is not only caused by electrical malfunctions (circuits open or shorted), but also by mechanical malfunctions such as control valve sticking, improper solenoid valve operation, etc.




DTC Logic

DTC DETECTION LOGIC






DTC CONFIRMATION PROCEDURE

CAUTION:
Always drive vehicle at a safe speed.

NOTE:
Immediately after performing any "DTC CONFIRMATION PROCEDURE", always turn ignition switch OFF.
Then wait at least 10 seconds before performing the next test.
1. CHECK DTC DETECTION
With CONSULT-III
1. Turn ignition switch ON.
2. Select "Data Monitor" in "TRANSMISSION".
3. Start engine and maintain the following condition for at least 30 seconds.

ACC PEDAL OPEN : More than 1.0/8
RANGE : "D" position
VEHICLE SPEED : Constant speed of more than 40 km/h (25 MPH)

With GST
Follow the procedure "With CONSULT-III".
Is "P0744 A/T TCC S/V FNCTN" detected?
YES - Go to "Diagnosis Procedure".
NO - Check intermittent incident. Refer to Intermittent Incident.




Diagnosis Procedure
1. CHECK LINE PRESSURE
Perform line pressure test. Refer to Component Tests and General Diagnostics.
Is the inspection result normal?
YES - GO TO 2.
NO - Repair or replace damaged parts. Refer to Component Tests and General Diagnostics.
2. CHECK TORQUE CONVERTER CLUTCH SOLENOID VALVE
1. Turn ignition switch OFF.
2. Disconnect CVT unit connector.
3. Check torque converter clutch solenoid valve. Refer to "Component Inspection (Torque Converter Clutch Solenoid Valve".
Is the inspection result normal?
YES - GO TO 3.
NO - Replace transaxle assembly. Refer to Exploded View.
3. CHECK LOCK-UP SELECT SOLENOID VALVE
Check lock-up select solenoid valve. Refer to "Component Inspection (Lock-up Select Solenoid Valve".
Is the inspection result normal?
YES - GO TO 4.
NO - Replace transaxle assembly. Refer to Exploded View.
4. CHECK OUTPUT SPEED SENSOR (SECONDARY SPEED SENSOR) SYSTEM
Check output speed sensor (secondary speed sensor) system. Refer to P0720.
Is the inspection result normal?
YES - GO TO 5.
NO - Repair or replace damaged parts.
5. CHECK INPUT SPEED SENSOR (PRIMARY SPEED SENSOR) SYSTEM
Check input speed sensor (primary speed sensor) system. Refer to P0715.
Is the inspection result normal?
YES - GO TO 6.
NO - Repair or replace damaged parts.
6. DETECT MALFUNCTIONING ITEMS
Check TCM connector pin terminals for damage or loose connection with harness connector.
Is the inspection result normal?
YES - Replace TCM. Refer to Exploded View.
NO - Repair or replace damaged parts.




Component Inspection (Torque Converter Clutch Solenoid Valve)
1. CHECK TORQUE CONVERTER CLUTCH SOLENOID VALVE





Check resistance between CVT unit connector terminal and ground.





Is the inspection result normal?
YES - INSPECTION END
NO - Replace transaxle assembly. Refer to Exploded View.




Component Inspection (Lock-up Select Solenoid Valve)
1. CHECK LOCK-UP SELECT SOLENOID VALVE





Check resistance between CVT unit connector terminal and ground.





Is the inspection result normal?
YES - INSPECTION END
NO - Replace transaxle assembly. Refer to Exploded View.