92 Galant dies on highway

Hi All,
My wife calls me today and says the 92 Galant LS dies on the highway as she was going to visit her out of town son. I will try to go the 30 miles tomorrow to retrieve the trouble codes(If I can) My question is is there a list of the possible codes somewhere I can retrieve and need a tutorial on how to retrieve. Any help is appreciated.
Chris

Let me get this right... Your wife's 92 Galant transmission was stuck in limp mode & you thought it was fixed by changing the ECU but it wasn't? Then you thought it was fixed by replacing the transmission control box & now it ended up on the side of the road? And if so why didn't she just continue driving it in limp mode to get home? Please clarify as I have a similar problem with my 91 Galant GSX stuck in limp mode after 12 times back to the tranny place & 3 times to 2 different electrical places & once to the dealer who won't touch it. Thank you in advance & if you could, leave your email.