1997 Catera with Engine Code P1700 Help!!!

Hi,
I have a 1997 Catera that I have just purchased a few months ago it has 58,600 miles on. Recently the transmission has been acting up, yesturday it would only drive in reverse, then I let it cool down and it started driving fine and then all the sudden transmission light and check engine light both came on, I turned the key off and restarted the car and the transmission light went away and the car started driving fine again, But the check engine light stayed on so I drove it to my local auto zone and the found the code to be P1700. Found out the engine code of P1700 meant Transmission Control Module (TCM) Request MIL Illumination. Can anyone please tell me what that code means in simple terms and what I need to do to repair my transmission so it does't keep acting up.

Thanks for all your help in advance,