Spare key not working. Battery seeems ok.

[Casa1862]

I've not used the spare key I have until yesterday (I know, should have tested it earlier!), when you press it the red light comes on but it doesn't do anything. I thought they might have mixed up the keys at the dealership when I purchased it but I opened the car using the hidden steel key (alarm went off) so must be the correct one. Is there anyway the key can be made to work or is it a dealer issue, car is still in warranty? 

The Battery was disconnected recently, not sure why that would affect the spare key, unless it happened to both and they repaired the one they had.

thanks 

 

 

[Richard1200]

In the title you say the Battery seems ok, do you mean the fob battery? As the most likely cause is the Battery in the fob. Plenty of UTube videos on how to change it.

[Casa1862]

Cheers, I think the replacement is CR2032,I'll try it. This key has never been used from new and our other one which is used every day is still ok, car is just under 2 years old and the red LED works when you press it hence I didn't suspect the Battery.

 

[BigChange]

Noticed your comment on "hidden steel key".  Is that hidden by you or does my IS have an externally accessible key hidden somewhere in the bodywork ?

[NemesisUK]

If your key fob is like mine, the mechanical key is 'hidden' in the fob, released by pressing the button on the side of the fob and pulling the tag at the top.

[rayaans]

Sounds like its faulty TBH. It should just work unless someone lost it and the replacement hasnt been programmed properly as it wont be coded which is what it sounds like.

[BigChange]

Well thanks Nemesis.  You live and learn!  Never knew it was there !

[Casa1862]

I changed the Battery and it's not that, both mechanical keys open the door so should be correct, however if you put the two mechanical key side by side there is very small differences, some of the groves are not identical. But close enough to open the door. All the numbers on both key fobs match. 

Could someone please look at both of their mechanical keys and have a look if there is a slight difference, maybe the machining is not that accurate which doesn't seem very Lexus  

Hopefully the key is the right one and the dealer will remarry them.