CVT: RE0F09B

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

P0744:

DTC Confirmation Procedure

CAUTION: Always drive vehicle at a safe speed.

NOTE: If "DTC CONFIRMATION PROCEDURE" has been previously performed, 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".
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 "Diagnostic Procedure".
NO >> Check intermittent incident. Refer to GI-42, "Intermittent Incident". Service Information For Electrical Incident

Diagnostic Procedure

1.CHECK LINE PRESSURE
Perform line pressure test. Refer to TM-242, "Inspection and Judgment". Line Pressure Test
Is the inspection result normal?
YES >> GO TO 2.
NO >> Repair or replace damaged parts. Refer to TM-242, "Inspection and Judgment". 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.

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.

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 TM-134, "DTC Logic". 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.
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 terminal 12 and ground.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Replace transaxle assembly.

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.