Why wont your automatic transmission shift into third gear?

Depending on the vehicle, lets say you own a Chrysler, the electronic transmission has a mode referred to as "limp in" mode. Your vehicle will run only in second, or maybe third gear(transmission). In most cases, if there is something mechanically wrong with your tranny, you will hear it or feel it, or have total failure.

In the case of an electronic problem, the check engine light accompanied by the inability to shift through the gears could be due to a faulty governer pressure sensor and or solenoid. Occasionally with Chrysler electronic trannys, the solenoid gets frozen and will not engage with the correct force. Fault code will indicate Governer pressure sensor voltage too low, etc. This can be remedied easily by purchasing the parts over the internet and dropping the transmission pan, removing the valve body, and replacing the two parts.