Have a read of this. Try it on your original key remote. Cost nothing to try. Don't worry about the battery part.
Hi
Last year l got my key fob copied, $100.00 No driving here, there, & everywhere in between trying to get it cheaper.
Earlier in the year my fob stopped working. Great l have the other one. Which of course works.
Couple of weeks ago l realised no spare. My original was still about so l thought l'd get a new case (ebay $4.75) & battery (jaycar $2.45).
Battery l got last week, case came yesterday.
I split the case with a large screw driver, then a smaller one. Checked with a multimeter how flat my battery was. To my surprise it wasn't flat at all. Showed full charge.
Anyway re shelled the electronics with the original battery, just pushed the case together, no glue, sealer or anything else. Put the original key in & screwed in the screws. Took out to car & pressed unlock button, no work, which didn't surprise me. Opened with key, no problem but the alarm went of. Put key in ignition & started it. Alarm stopped its noise. While key was still in ignition l pushed the lock button (on the fob & it locked) then pushed the fob unlock button & it unlocked. I believe this is called re-syncing. Cool. That is probably all l needed to do to have the fob working, was to re-sync it.
Just got myself a spare key & a spare battery for $7.20. Still cheap, so l'm happy.
Hope this can help some one else.
Lex