DTC P0744 A/T TCC S/V Function (Lock-Up): Description

WARNING: This page is about a different car, the 2007 Nissan Maxima. However, it is still accessible from the selected car via links, so may be relevant.

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.