Spare fob hidden inside the Prius

Urban legend.

Relaying remote entry system signals via telephone might work if the signals were sound-based, but they’re not. An RKE system transmits an encrypted data stream to a receiver inside the automobile via an RF (radio frequency) signal, a signal that can’t be effectively relayed via cell phone.

 

I am a ham, tech etc. have tried it? Mabe the older fobs only. Dying to try it though just for kicks.

 

Replaying a recording of the FOB signal won't work with modern FOBs. There is a rolling code that is included in the encrypted message. Once the code has been used, a new one is required.

A recording of the FOB signal would work if the car doesn't receive it and the sequence number is within the acceptable range.

Older FOBs didn't use a rolling code, so replay would work. The lore is correct, but obsolete.