Certain vehicles may have been assembled with a transmission range sensor (TRS) that was calibrated out of specification for reverse gear. If this condition exists, the transmission may not properly engage reverse gear and/or if reverse gear does engage, the "R" indicator on the dash or the backup lamps may not illuminate. These conditions increase the risk of a crash or a pedestrian being struck due to the vehicle's not signaling it is in reverse. Dealers will inspect and replace the transmission range sensor as necessary to correct this concern. The Ford recall number is 12C23.