CVT

P0744 TORQUE CONVERTER

Description

- The torque converter clutch solenoid valve is included in the control valve assembly.
- 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.


CONSULT Reference Value in Data Monitor Mode

Remarks: Specification data are reference values.







On Board Diagnosis Logic

- This is an OBD-II self-diagnostic item.
- Diagnostic trouble code "P0744" with CONSULT is detected under the following conditions.
- When CVT cannot perform lock-up even if electrical circuit is good.
- When TCM compares difference value with slip revolution and detects an irregularity.


Possible Cause

- Torque converter clutch solenoid valve
- Hydraulic control circuit


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 and wait at least 10 seconds before performing the next test.
After the repair, touch "ERASE" on "SELF-DIAG RESULTS" and then perform the following procedure to confirm the malfunction is eliminated.

WITH CONSULT

1.Turn ignition switch ON. (Do not start engine.)
2.Select "DATA MONITOR" mode for "TRANSMISSION" with CONSULT.
3.Start engine and maintain the following condition for at least 30 seconds.





4.If DTC is detected go to .

WITH GST

Follow the procedure "WITH CONSULT".


Diagnosis Procedure


1. CHECK INPUT SIGNALS





1.Start engine.
2.Select "ECU INPUT SIGNALS" in "DATA MONITOR" mode for "TRANSMISSION" with CONSULT.
3.Start vehicle.
4.Check if there is a great difference between "ENG SPEED SIG" and "PRI SPEED SEN". (Lock-up ON.)





OK or NG
OK- GO TO 5.
NG- GO TO 2.

2. CHECK LINE PRESSURE

Perform line pressure test. Trouble Diagnosis.
OK or NG
OK- GO TO 3.
NG- Repair or replace damaged parts. Trouble Diagnosis.

3. DETECT MALFUNCTIONING ITEM

Check the following:
- Torque converter clutch solenoid valve. CVT.
- Lock-up select solenoid valve. P1740.
OK or NG
OK- GO TO 4.
NG- Repair or replace damaged parts.

4. CHECK SECONDARY SPEED SENSOR SYSTEM AND PRIMARY SPEED SENSOR SYSTEM

Check secondary speed sensor system and primary speed sensor system.
OK or NG
OK- GO TO 5.
NG- Repair or replace damaged parts.

5. CHECK DTC

Perform DTC Confirmation Procedure, (see above).
OK or NG
OK-INSPECTION END
NG- GO TO 6.

6. CHECK TCM

1.Check TCM input/output signals. Trouble Diagnosis.
2.If NG, re-check TCM pin terminals for damage or loose connection with harness connector.
OK or NG
OK-INSPECTION END
NG- 1.Repair or replace damaged parts.
2.Replace the transaxle assembly. Transaxle Assembly.