It sounds like the gearbox control cable is out of synchronisation, and needs adjustment.
The cable turns a crank on the bottom of the box, which then links a rotating rod through the box to the switch module on the top.
The gear selector lever has sensors, which light the lights, and also tell the TCM where the lever is. The TCM also gets signals from the box switch module, and compares the two. If the cable adjustment isn't correct, then the TCM gets conflicting data, so it assumes a fault, and sends the F4 signal to the dash LCD. There is a setting procedure in the workshop manual, which needs to be followed to set the relative positions, or it'll never work correctly.
The cable turns a crank on the bottom of the box, which then links a rotating rod through the box to the switch module on the top.
The gear selector lever has sensors, which light the lights, and also tell the TCM where the lever is. The TCM also gets signals from the box switch module, and compares the two. If the cable adjustment isn't correct, then the TCM gets conflicting data, so it assumes a fault, and sends the F4 signal to the dash LCD. There is a setting procedure in the workshop manual, which needs to be followed to set the relative positions, or it'll never work correctly.