two different key fobs in one prius

I did experience what happened to you. A friend bought a Barcellona Red Prius III, similar to my Bar. Red IV, and I was trying to give her pointers on the display and how to get higher mpg's. I sat in the driver's seat but I couldn't start it because of the "key not detected" issue. She was also sitting in the passenger seat with her purse on the floor as usual. I handed my key to another friend outside the car and had no issues starting after that. Weird - it should be able to recognize the right key even with multiple keys inside the car.

 

This depends on the radio protocol. If both keys are talking back to the car's receiver at the same time, the messages can be corrupted -- did you ever hear two AM stations on the same frequency? -- or only the one closer to the receiver will be heard -- did you ever hear an FM radio jumping between two stations on the same frequency when traveling through rolling hills?

There are multiple ways around this, as is done with cell phones. But without knowing more radio details, we don't know if Toyota applied any of them.

 

I often have a 2008 and a 2010 key in either of the cars. I never have had a problem. I guess that if key sequence/code is nearly identical you might have a problem.

 

This problem has been reported by several Gen III owners. As yet there is no resolution, other than working around the problem. If necessary, you can always hold one of the fobs up to the button to utilize the near-field RFID chip, which will allow your Prius to start.

Tom

 

I did encounter the same problem with two keys fobs in the same vehicle, both 2011, I followed the MFD instruction to turn on the Prius with the fob actually pushing the starter button, problem solved. I really don't see this as a " problem"' it is more of security screening. The Prius is just checking that everything is on the up and up and that the right fob is trying to turn on the vehicle. We figured out the problem with my passenger found his fob in his pocket prior to our golf outing, on the return trip home, we tested our theory and he stood outside of the car, then placed the fob in his golf bag, problem solved. I wished my golf score was so easy to correct.

 

we have a 2010 4 and our daughters have a2011 we have the same problem the dealer didnt know what to do whoever is going in whoevers prius either holds their keys out the window real far stays away from the car until its started or has to leave their key at home

 

This is a work-around. The smart key system gets confused by two working fobs. It shouldn't, but it does. Pressing the start button with the fob allows the Prius to start because each fob contains a backup near-field RFID device that works independently from the smart key system. The RFID chip must be very close to the reader, hence the need to hold the fob up to the button. RFID doesn't need a working fob battery, so it also serves as the backup when your fob battery dies.

Tom

 

Why not program both cars to accept all the fobs? That way you only each need to carry one fob, and can use either car, and neither car will get confused by a fob it doesn't recognize.

 

I have a 2011. My friend has a 2012. We either take his or my Prius to lunch... We have seen the interference twice inside my 2011, but we haven't seen interference inside his 2012 yet... Perhaps, my 2011 key fob battery is a year older and just a bit weaker

 

Since my son got his Gen 3 Prius, we have been a 3 Prius family; all are Gen 3. On a few occasions, we have had FOBs for all three Prii in the same car, with no apparent conflicts in any of the three Prii. Like sibling rivalry, there may be some FOB combinations that cause interference. When our children were younger, we found that it was easy to prevent sib-rivalry problems by separating the offenders. Perhaps you should consider moving your wife, and her disruptive FOB, to a back seat. A safer, albeit less entertaining, approach to isolating this apparent FOB-rivalry problem could involve temporarily removing the batteries from the extra, unpaired FOB, and then see if the problem persists. Both FOBs will still emit a signal, but the battery-less one should be substantially weaker. Once you understand and document the problem, you could throw it back to your Toyota dealer and demand that they reprogram the FOBs for one or both of your cars, so they work as advertised.

 

We have four 2012's and one 2011 in our coffee group no problem riding in the 2012's, but when the 2012's ride with the 2011, always have the problem! Is it a 2011 problem??? I think so.

 

We have 2 identical 2010's/tech pkg. No issues with fobs in the last 3 years, although the fob battery is getting low on one of the cars. It display's "key fob battery low" and beeps after I turn the car off. The other cars good battery fob still doesn't interfere with the low battery fob. Must be a radio frequency thing...

 

Could you imaging if all vehicle transponder keys interfered with each other? It would be really difficult to carry passengers. An oops! for Toyota.

 

My husband reports that while going to lunch a coworker's 2010 Prius got confused when our 2011 fob was aboard.

 

sigh me and my friend have this same exact issue. I have a 2013 Prius Four, not IV as uppercase roman numerals were used for mode year 2010, and he has a 2011 Lexus CT. kinda sad that there's nothing that can be done. after skimming through this thread.

 

Well, you could wrap the unneeded fob in aluminum foil, or put it in an altoids tin, or something like that...

 

We have two 2010 prii and my wife keeps both fobs in her pocket book; with no problem the last 4 years.