The best way to determine what is wrong with the seat mechanism would be to remove the seat and inspect the under side. If you remove the upholstry all you will see is a metal seat pan. You have to remove the seat first to service the seat cover anyways.
Refer to Disabling the SIR System.
Remove the seat from the vehicle. Refer to Front Seat Replacement - Bucket . Remove the seat trim panel. Refer to Front Seat Trim Panel Replacement . Remove the outboard seat belt anchor nut. Pull the belt through the seat cushion. Remove the front nuts (2) on the underside of the seat cushion. Unsnap the lumbar cable (6) (disconnect the lumbar wire harness if equipped with power lumbar). Lift the seat cushion up off the rear plastic holders (1) on the underside of the seat cushion, and pull forward. Remove the seat switch bezel. Refer to Driver Seat and Passenger Seat Adjuster Switch Bezel Replacement . Remove the lumbar actuator (5). Unclip the seat trim cover from the seat cushion frame. Using a side motion, carefully separate the seat cushion trim cover from the seat cushion pad. Remove the pad from the seat cushion frame. Remove the seat cushion heater element, if equipped. Refer to Driver Seat and Passenger Seat Cushion Heater Replacement . Installation Procedure
I am sorry. I misunderstood your original question. The back cover has a J channel at the bottom, use a screw driver or bent pick to assist in separating this. Once you have the cover pulled up, you can inspect the mechanism. You may have a bolt or two backed out, if so reinstall them with some loctite.
Caution: This vehicle is equipped with a Supplemental Inflatable Restraint (SIR) System. Failure to follow the correct procedure could cause the following conditions: