How A Replacement EPROM Or Control Module Is Determined: TCM
Regarding the replacement EPROM for Transmission Control Modules there are specific Service Bulletins which identify various situations that can be addressed by replacing the EPROM in the control module. The replacement transmission EPROM does not require any type of programming after being installed, as it already contains all the program and operational data.
If an early version Transmission Control Module, for vehicles prior to 1996 model year, is replaced it generally also does not need to have the EPROM replaced as the required program is already installed.