Modern vehicle automatic transmissions are monitored by various sensors and are also controlled by solenoids and regulators. All of these electronic components, which are necessary for the transmission to function properly, are housed in the TCM (Transmission Control Module).
Like the vehicle’s other modules, the TCM looks for feedback on some electrical signals when a solenoid is activated. In this way, it determines if any component has malfunctioned, at which time the TCM sets a DTC code.
In this case, the P0701 OBDII diagnostic code refers to a fault in the transmission control system. This fault is not specific, therefore, a diagnostic test is necessary to determine the cause.