Vehicles with automatic transmissions have a determined amount of shift solenoids, which are used to manage the transmission fluid flow through the various transmission channels. These solenoids tell the control module if the pressure with which the fluid is sent is the right to achieve the gear changes properly.
If the PCM (Powertrain Control Module) determines that the shift solenoid “A” has a lock-up condition, the fault code P0752 OBD2 will be set.