I have two keys for my land rover defender 90 2010
Iam having trouble with the ignition,the keys are kept separate I turn the ignition on and the vehicle won't start the horn sound's twice.
I then get the spare key and the vehicle starts with this key.
After turning the ignition off the vehicle will then not start again using the key I have just started it with. I can then get the other key that would not start the vehicle and it then starts the vehicle . I have kept the two keys separate and not together when Iam trying to start the vehicle.
Any ideas.
Dave p

You're fobs are picked up by a transceiver coil around the barrel
Does the problem fob have a good battery ie does the alarm led flash fast etc to warn of low fob battery?