H thank you for your question hope this helps.
The transmission control module also known as Power train Control Module (PCM)
needs to be replaced.The PCM is located in the upper dashboard area, in back of the instrument cluster assembly. The PCM utilizes signals from a variety of sensors to optimize control of the engine, trans axle and various accessories. The PCM is a microprocessor-based computer that is the main component of the power train control system. The PCM contains either one or two separate controllers located in one unit. The manual trans axle version contains only an engine controller, while the automatic trans axle version contains both an engine and trans axle controller.
The PCM contains an Electronically Erasable Programmable Read Only Memory (EEPROM), which stores information necessary for proper vehicle operation. Whenever the PCM is replaced, this memory must be reprogrammed in order for the vehicle to operate. The vehicle may not even start if this is not done. Only a dealer/service station equipped with the Saturn Service Stall System, or an equivalent EEPROM reprogramming computer, will be able to properly calibrate the PCM.
It is fairly easy to do hear is the steps to replace.
Hope this helps