Maybe two Prius in family

gcruik · 10-23-2005, 11:14 PM

I have one 05 Prius, standard key thingey that I have to stick into the dash to make the car work.

If I get another Prius in 06, can I get one key lump to run both cars?

I can not imagine putting two of those lumps into my pocket. I suspect that others will think that somthing else is going on in my jeans.

I love this car. And I need a new set of wheels.

Gordon in Menlo Park

tumbleweed · 10-24-2005, 12:21 AM

There is a topic in the Prius Main Forum called "lost my smart key fob in the car" that my have some information you can use even though yours is not SKS. I think the answer is no because there is some kind of complex algorithm that is unique to each car, so once the fob is programmed it can only work with one car.

DanMan32 · 10-26-2005, 10:42 AM

I disagree. One fob I believe can be registered by more than one vehicle. It is the car that registers the fob, and not the other way around. I believe a non SKS car can register an SKS fob, and an SKS car can register a non-SKS fob, though of course the SKS feature would could not be registered, and would not work with that pairing.

The only way you might come to a problem is if the 'common' fob was away from one vehicle for more than say 255 executions, after which the car and fob would be out of sync, thus requiring to be re-registered as if it were a new fob.

The fobs generate a psudo-random code sequence, who's next code can be predicted by a complex algorithm, assuming the last code was known. If a code send by the fob was missed by the car, when it received the subsequent code, it sees if it matches one of the next 255 codes it would expect to get from the last one it accepted. This is also how a rolling code garage door system works.

mmcdougald · 10-28-2005, 11:18 PM

I see one issue if this does work. if you have one fob and the battery dies you only have one normal key and a 50/50 chance of being in the correct car for the key to unlock it.

DanMan32 · 10-31-2005, 04:45 PM

That's a good point. Make a copy of the mechanical key and store it somewhere, or get a credit card key made.

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10-23-2005, 11:14 PM	#1
gcruik Join Date: Sep 2005 Posts: 4 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	I have one 05 Prius, standard key thingey that I have to stick into the dash to make the car work. If I get another Prius in 06, can I get one key lump to run both cars? I can not imagine putting two of those lumps into my pocket. I suspect that others will think that somthing else is going on in my jeans. I love this car. And I need a new set of wheels. Gordon in Menlo Park

10-24-2005, 12:21 AM	#2
tumbleweed Senior Member Join Date: Oct 2005 Location: Eastern Oregon Posts: 1,005 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	There is a topic in the Prius Main Forum called "lost my smart key fob in the car" that my have some information you can use even though yours is not SKS. I think the answer is no because there is some kind of complex algorithm that is unique to each car, so once the fob is programmed it can only work with one car.

10-26-2005, 10:42 AM	#3
DanMan32 Join Date: Aug 2004 Location: Tampa Bay, FL Posts: 3,775 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	I disagree. One fob I believe can be registered by more than one vehicle. It is the car that registers the fob, and not the other way around. I believe a non SKS car can register an SKS fob, and an SKS car can register a non-SKS fob, though of course the SKS feature would could not be registered, and would not work with that pairing. The only way you might come to a problem is if the 'common' fob was away from one vehicle for more than say 255 executions, after which the car and fob would be out of sync, thus requiring to be re-registered as if it were a new fob. The fobs generate a psudo-random code sequence, who's next code can be predicted by a complex algorithm, assuming the last code was known. If a code send by the fob was missed by the car, when it received the subsequent code, it sees if it matches one of the next 255 codes it would expect to get from the last one it accepted. This is also how a rolling code garage door system works.

10-28-2005, 11:18 PM	#4
mmcdougald Join Date: Sep 2005 Location: Philadelphia, PA Posts: 8 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	I see one issue if this does work. if you have one fob and the battery dies you only have one normal key and a 50/50 chance of being in the correct car for the key to unlock it.

10-31-2005, 04:45 PM	#5
DanMan32 Join Date: Aug 2004 Location: Tampa Bay, FL Posts: 3,775 My Car: Package: Nominated 0 Times in 0 Posts TOTM Awards: 0 Friends: 0	That's a good point. Make a copy of the mechanical key and store it somewhere, or get a credit card key made.