I have a '98 406 TD, my key seems to have become unreliable as far as operating the central locking is concerned. It will only lock/unlock remotely 50% of the time. I have changed the batteries and cleaned the contacts (as best I can) to no avail. My wifes key works fine. Is it a 'known' problem for the keys to become unreliable as far as central locking operation goes? I'm betting that a new key will cost an arm and a leg.