None of my SKS key fobs lock/unlocks doors

Hi everyone,

We've been having trouble with our SKS fobs for our '04 Prius ever since we had them replaced by a dealer two years ago. We lost one, bought a new fob and had it programmed. After programming, the old fob we still had wouldn't open or close any doors anymore. The dealer then replaced that one as well so we had two working keys again. We had to pay €350 for the privilege (about US$500).

After year or so, one of them stopped opening doors using the buttons on one of the fobs, then a couple of months ago that fob also stopped doing the SKS thing, and now the other one has stopped doing both as well.

Both still work when inserted into the slot, I can still start the car with either.

I have tried the procedure described here with the existing fobs, the car enters into 'add' mode for both fobs. As this requires you to press the buttons on the fob, I think this means the fobs are actually still working and still registered with the ECU/SKS system in the car. When I try to add the other fob, it responds with the double-lock/unlock signalling it didn't accept the fob.

Batteries in the both fobs are good. I disconnected the 12v battery for about two minutes - maybe a reset would work. But no.

I'm hesitant to do the forget-all-except-master fob procedure, for one because I probably can't reregister the other fob anyway and more importantly - I don't know how to confirm they're even the master fobs and not #3 and #4 because the dealer didn't do the procedure before.

Has anyone else had this happen?