[Davescort97]

The O/D light indicates there's a problem with the transmission. The diagnostic trouble code needs to be read by the dealer or a transmission shop. Not downshifting could be caused by a defective vehicle speed sensor (VSS) in the tail end of the transmission. It's easy to get to and not that expensive at the parts place. Your transmission not shifting into Drive or Reverse could be caused by low fluid level or the front pump is not putting out enough pressure to get it to shift. Check your fluid condition by putting a drop of ATF on a paper towel. If it spreads out it is okay. If it doesn't it should be replaced.