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 malfunction (circuits open or shorted), but also by mechanical malfunction such as control valve sticking, improper solenoid valve operation, etc.

DTC Logic

DTC DETECTION LOGIC

1. Turn ignition switch ON.
2. Select "DATA MONITOR".
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 See: Testing and Inspection\Initial Inspection and Diagnostic Overview\Service Information For Electrical Incident\Intermittent Incident.

Diagnosis Procedure
1.CHECK LINE PRESSURE
Perform line pressure test. Refer to See: Transmission and Drivetrain\Continuously Variable Transmission/Transaxle\Description and Operation\CVT RE0F09B\Line Pressure Test.
Is the Inspection result normal?
YES >> GO TO 2.
NO >> Repair or replace damaged parts. Refer to See: Transmission and Drivetrain\Continuously Variable Transmission/Transaxle\Description and Operation\CVT RE0F09B\Line Pressure Test.
2.CHECK TORQUE CONVERTER CLUTCH SOLENOID VALVE

1. Turn ignition switch OFF.
2. Disconnect CVT unit harness 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 See: Transmission and Drivetrain\Continuously Variable Transmission/Transaxle\Service and Repair\CVT RE0F09B\Transaxle Assembly\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 See: Transmission and Drivetrain\Continuously Variable Transmission/Transaxle\Service and Repair\CVT RE0F09B\Transaxle Assembly\Exploded View.
4.CHECK OUTPUT SPEED SENSOR (SECONDARY SPEED SENSOR) SYSTEM
Check output speed sensor (secondary speed sensor) system. Refer to DTC Logic.
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 See: P0715\CVT RE0F09B.
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 See: Powertrain Management\Transmission Control Systems\Control Module, CVT\Service and Repair\CVT RE0F09B\Exploded View.
NO >> Repair or replace damaged parts.

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