It's possible the wire has been severed to the O/D button. It happened to mine. Here is what you need to do to check.
There is a small clip on the front of the shifter that just barely sticks out a slit in the front facing toward the dash. Then you need to do take a screw driver or something you can find to fit behind the clip and pry it out. With the clip out the shifter should slide upward. Slowly lift it up, and not too far off the base because you don't want to wank the wire from inside the shifter.
When I checked my wire it was cleary bent so far in half that it severed one of the wires. So I reattatched the pieces, covered it in electrical tape and slid the shifter back on. If the wire has fallen inside the shifter base you will need to remove the shifter face plate.
If that happens first off remove the center console from around the shifter. You'll need to remove the rubber piece in the cup holder, underneath is a small screw. After you unscrew that if you lift up the console should come loose from the latches holding it in place. With that removed I believe there are two screws holding the plate in place once you remove those you should see the wire on the other side of the shifter. Just make sure that you get the shifter plate aligned with the shifter when you put it back on otherwise it will always show the car in low 2 or something.
Did that make any sense? squint
