Nissan Versa (N17): P0744 Torque converter

Description

This DTC is detected when the torque converter clutch solenoid valve is electrically normal but the torque converter clutch does not engage. This is not due to an electrical malfunction (circuit open or shorted), but is instead due to a mechanical malfunction (sticking of the control valve, malfunction of the solenoid, etc.).

DTC Logic

DTC DETECTION LOGIC

DTC	Trouble diagnosis name	DTC detection condition	Possible causes
P0744	Torque Converter Clutch Circuit Intermittent	The following diagnosis conditions are met, and the torque converter slip speed is at or above a set value (40 rpm + Vehicle speed / 2) continuously for 30 seconds or more. - Diagnosis condition - Lock-up pressure difference: More than Max. lock-up pressure difference × 0.95	- Torque converter clutch solenoid valve - Control valve assembly - Torque converter

DTC REPRODUCTION PROCEDURE

CAUTION: Be careful of the driving speed.

1.PREPARATION BEFORE WORK

If another "DTC CONFIRMATION PROCEDURE" occurs just before, turn ignition switch OFF and wait for at least 10 seconds, then perform the next test.

>> GO TO 2.

2.CHECK DTC DETECTION

1. Drive the vehicle.
2. Maintain the following conditions for 35 seconds or more.

Selector lever : D position

Vehicle speed : 45 km/h (28 MPH) or more

    3.   Stop the vehicle.

    4.   Check the first trip DTC.

Is "P0744" detected?

YES >> Go to TM, "Diagnosis Procedure".

NO >> Check intermittent incident. Refer to GI, "Intermittent Incident".

Diagnosis Procedure

1.CHECK LINE PRESSURE

Perform line pressure test. Refer to TM, "Work Procedure".

Is the check result normal?

YES >> GO TO 2.

NO >> Repair or replace the malfunction items.

2.CHECK TORQUE CONVERTER CLUTCH SOLENOID VALVE

1. Turn ignition switch OFF.
2. Disconnect the A/T unit connector.
3. Check the torque converter clutch solenoid valve. Refer to TM, "Component Inspection (Torque Converter Clutch Solenoid Valve)".

Is the check result normal?

YES >> Check intermittent incident. Refer to GI, "Intermittent Incident".

NO >> Repair or replace the malfunction items.

Component Inspection (Torque Converter Clutch Solenoid Valve)

1.CHECK TORQUE CONVERTER CLUTCH SOLENOID VALVE

Check the resistance between the A/T unit connector terminal and ground. 

Is the check result normal?

YES >> INSPECTION END

NO >> There is a malfunction of the torque converter clutch solenoid valve. Replace the transaxle assembly. Refer to TM, "Removal and Installation".