Nissan Maxima Service and Repair Manual: P0740 torque converter

Description

The torque converter clutch solenoid valve is activated by the TCM in response to signals sent from the vehicle speed and accelerator pedal position sensors. Lock-up piston operation will then be controlled.
Lock-up operation, however, is prohibited when CVT fluid temperature is too low.
When the accelerator pedal is depressed (less than 2.0/8) in lock-up condition, the engine speed should not change abruptly. If there is a big jump in engine speed, there is no lock-up.

DTC Logic

DTC DETECTION LOGIC

DTC CONFIRMATION PROCEDURE

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

With GST

Follow the procedure "With CONSULT".

Diagnosis Procedure

Regarding Wiring Diagram information, refer to TM-126, "Wiring Diagram".

1.CHECK TORQUE CONVERTER CLUTCH SOLENOID VALVE CIRCUIT

Turn ignition switch OFF.
Disconnect TCM connector.
Check resistance between TCM vehicle side harness connector terminal and ground.

2.CHECK HARNESS BETWEEN TCM AND CVT UNIT (TORQUE CONVERTER CLUTCH SOLENOID VALVE) (PART 1)

Disconnect CVT unit connector.
Check continuity between TCM vehicle side harness connector terminal and CVT unit vehicle side harness connector terminal.

3.CHECK HARNESS BETWEEN TCM AND CVT UNIT (TORQUE CONVERTER CLUTCH SOLENOID VALVE) (PART 2)

Check continuity between TCM vehicle side harness connector terminal and ground.

4.CHECK TORQUE CONVERTER CLUTCH SOLENOID VALVE

Check torque converter clutch solenoid valve. Refer to TM-68, "Component Inspection (Torque Converter Clutch Solenoid Valve)".

5.DETECT MALFUNCTIONING ITEMS

Check TCM connector pin terminals for damage or loose connection with harness connector.

Component Inspection (Torque Converter Clutch Solenoid Valve)

1.CHECK TORQUE CONVERTER CLUTCH SOLENOID VALVE

Check resistance between CVT unit connector terminal and ground.