Problem With Remote Key Not Working

[Luthier]

I have a 2 litre D4D 2008 Avensis with the usual 3 button remote key. The problem I have is related to one of the 2 keys I have. One works fine and the other usually works ok but recently on 3 occasions, the remote has failed to unlock the doors. I also noticed that when it doesn't unlock the doors the little red led does not light which to my mind indicates the problem lies with the key itself. I have changed the Battery and when it does work it will unlock the car from 20-30 metres away. When it first happened I thought never mind I'll use the key manually. Unfortunately this sets off the alarm!

Is there a way of unsetting the alarm manually?

Also - am I able to replace the electronic 'box' within the key as it seems this may be the source of the problem. Any help would be much appreciated.

[autolocksmiths]

most likely the micro switch inside is broken {common fault}

[Q.S.]

most likely the micro switch inside is broken {common fault}

I had similar problems and fitted new microswitches to it. No problems since. Have a search on eBay for the switches. A bit fiddly to replace, you will need a small needlepoint soldering iron and probably a magnifying glass.

[Luthier]

Sorry for the late reply and thanks to both of you for the info.

Interestingly I started using my spare key (which had never been used since the car was new) and within a week I had the same problem! I discussed it with my Toyota dealer who suggested that it may be that I also have a computer memory stick and small torch on my key ring. When I sit down at home or at work, the memory stick or torch presses on the buttons and the key turns itself off after a while. If I then go to the car and try it, the remote will not work. So two weeks ago I removed them from the key ring and so far there's not been a repeat of the problem! Fingers crossed that it's so simple.