royboy

I have a 2002 Grand Voyager up until recently was working great, now the engine management light has come on and it seems to just be driving in third gear all the time, wont change up or down. A mate plugged in diagnostic machine and said it was a sensor issue changed the sensor and it still will not move up and down the gears, any help would be really appreciated as I love this motor and dont want to change it. Cheers Royboy