Hello,The transmission is in limp mode due to a faulty electronic component. Usually, the electric plate mounted to the valve body goes out and needs to be replaced. To confirm this, transmission control unit fault codes must be read out. All of the electronic components can be replaced without removing the transmission. Of course, transmission fluid has to be checked for any metal shavings. If they are found, that is an indication of more serious mechanical damage. If oil is OK, it should be changed out as well.