What is the reason for the Ford Fiesta not responding when shifting gears?

[VanAlan]

Issues with the transmission or problems with the coupler can cause an automatic transmission car to not respond when shifting gears. The specific cause depends on the fault code retrieved, as different transmissions may exhibit different faults. While driving, the car may suddenly experience poor acceleration performance, as if the transmission has shifted into neutral, causing the car to gradually come to a stop. Alternatively, when shifting gears to start, the car may not move. During diagnosis, the first step is to determine the location of the fault. Relevant information about the transmission is as follows: 1. Introduction: A device that changes the speed ratio and direction of motion. It is used to alter the torque, speed, and direction of motion transmitted from the driving shaft to the driven shaft under different working conditions. A gear-driven transmission generally consists of a housing and several gears. 2. Function: While driving, to adapt to different conditions, the car's driving force and speed need to vary within a certain range. However, the existing engine's torque and speed variation range cannot meet this requirement, hence the need for a transmission.