Why won't my car go in reverse?
When I put my car in reverse, it won't move.
Most frequent cause for this is low transmission fluid; check it. If fluid is OK, it might be loss of fluid pressure due to wear or an internal defect. Might be a dirty selector switch. Make several rapid changes from park, through reverse and to neutral; this might free it up. Or it might be damaged linkage if it feels like shifts into gears are not precise.