I have a 2010 A5, my issue is I get a message in the cluster saying the keyless entry key is defective when I press the start button, the car will not start. The only why I can get the car to start is to insert the key. Both my key fobs are doing the same thing. I have tested the batteries and both are reading 3volts, plus when I insert the battery I get one blink from the red light on the fob which indicates the battery is OK.

Any suggestions...Please: