Trany is in limp mode

[scoobydoo092]

i have had my 2002 grand caravan in several times . every time it is stuck in second gear and does not shift. engine light is on all the time and i can not drive past 40 because the car races. have replaced the tcm and the soleniod. all brand new. the scanner always reads 888 transmission relay. please help me i can not find any thing else wrong