The Peugeot 508 automatic gearbox is locked, with only third gear. What is the reason for mastering maintenance download?

The Peugeot 508 automatic transmission is locked, and only the third gear is the failure of the transmission control module. Peugeot 508 automatic transmission can only lock the third gear. The failure of the internal control module of the gearbox is caused by the bad accelerator position sensor or accelerator pedal position sensor, which will affect the normal operation of the gearbox and need to be repaired in time.