Dodge Repair: automatic doesnt change gears, automatic transmisson, dirty oil

Question
I have a 1997 intrepid that is an automatic transmisson.  Recently it started not switching from low gear to the high gear. the power seems to
be cut in half.  Check engine light stays on.  Could this problem come from dirty oil?

Answer
hello
bring it to a tranny shop they do a free diagnostiac test i belive it is a shift senser it is one out of 6 you can try reseting the compuiter by takeing off the neg. cable off the battery for 5 min and it might reset the tranny please rate my serivice pete