Relearnig key fob

[Renee]

How do you reprogram your key fob to new computer

 

[scotman]

The technician should have done that as part of the process of replacement of the controller. I think you should replace the batteries in both of the Key fobs with new, brand name, batteries. Also have the vehicle battery "load tested" prior to having the work done.
It really can't be underemphasized how important battery condition is in the reliable and economical function of your Fiesta!
A weak battery will cause the alternator to run more frequently (or continually!) Which hurts fuel economy and causes the engine to work harder just to supply the electrical demands.
Many of the processors and modules have very specific power supply requirments. When the electrical system suffers from low capacity, it becomes possible for the system to have drops or spikes in the available electrical power to the various systems. It would be an understatement to say that it is not good for the functionality of the car and can cause controllers and modules to possibly get fried.