Where is the transmission shift solenoid in the tranny pan

 

You must have a reason for asking. There are several shift solenoids and you need to know which one you are after.

A word of caution, however, just because a code might suggest a particular possible solenoid problem does not necessarily mean the solenoid is defective.
You need to verify all connections are good and clean and the solenoid is getting the signal to operate or you could go through a lot of trouble and work only to still have the same problem