key fault?

my daughter used her car to go shopping, when she returned to the car park later, and pressed her key fob it did not work, cental locking didn;t work and immobiliser did not disarm, changed batteries in fob made no difference, breakdown guy came out checked the key says its working but the immobiliser may be faulty, for both faults to occure within a short period to me sounds unsual, i have entered a code into the car via central locking button on console, and this allows me to start and drive the car, but i have to do this every time i want to use it, is there away of reseting the key to the immobiliser, please