2004 Peugeot 307 automatic broblem (indication)

I have a Peugeot 307 automatic and before one month I had an accident ! The motor has to separate from the car body so they can fixed. When the car finally fixed after one week of driving the gear indication in the dashboard is blinking (flashing) in position N or D and you can not put it to manual mode! Some times you put it to drive position and it blinks (Flashing) the symbol R position or N it depends where it stuck but the car change gears normally! The problem appears and disappears, I have make a diagnosis and the computer says temporary failure of digital signal! I check the contacts of the automatic gear computer and they seams ok! What else can I do?