Vehicles with automatic transmissions are equipped with a Torque Converter Clutch (TCC). The TCC is located between the engine and the transmission. Its purpose is to increase the torque output of the engine and to control the rear wheels.
There is a coupling system between the engine and transmission that multiplies torque, resulting in equal speeds. There is minimal difference between the engine RPM and transmission input RPM. To achieve this, TCC solenoids are used, which are controlled by the Powertrain Control Module (PCM) or Transmission Control Module (TCM. They send hydraulic fluid and engage the clutch, creating a strong coupling and increased efficiency.
DTC P0744 OBDII is set when the PCM or TCM finds a fault in the TCC solenoid circuit.