Assuming a two button plip (fob) your car may have lost contact with it. (Although the key code should get you going.) Not usre what the 'electronics company' did to check it. (I used to have a a gadget that checxk if it was transmitting and if that is what they did my first answer stands. You need to go to a dealer, with the plip, and have the car plugged into a diagnostic laptop.
Remember the above answer is all based a two button plip - not a one button type.
t
August 2007