remote entry -key fob programming

[maxpower]

maxpower, there is nothing in this description that would preclude the original poster from programming the same keyfob to open multiple cars - as long as the keyfobs were the same part number AND as long as the system didn't have a different set of pseudo random number generators. (PRNGs)

If for example the transmitter had a table of, lets say 200 different PRNGs, and during keyfob programming the transmitter uploaded a selected PRNG to the keyfob, then you would have a problem doing it. What would happen is both vehicles would likely use a different PRNG.

But, if the PRNG's are only different between vehicle models, and or years, and the PRNG was burned into the keyfob, then as long as both cars used the same PRNG you could do it.

Keep in mind that when you program one remote on this system you have to program all at the same time. Or it wipes out the ones that you didnt program.

I can guarentee to you that at least up to 1995 Chrysler did in fact use fixed PRNGs in the RKE system. In fact the sequence generator was the same algorithim for multiple YEARS. That is why I was able to program both my '94 and '95 van to use the same keyfobs.

You were able to do your older vehicles because it was not using the rolling code system I would think. when program a key fob into that year you didnt have to have all of them to reprogram. You were able to add one

They changed the remotes in 96, and I would assume the system as well. But, if the new keyfobs are transmit-only, then it would be very likely that keyfobs of the same part number would use the same PRNG and would work.

Frankly the entire system is way overengineered. A thief simply walks up to the car and smashes the window with a rock, he does not bother fiddling around with sniffing RKE signals.

I beleive the key fobs were designed more to lock and unlock doors easier.... not to deter thiefs. The skim key is to deter thiefs from stealing the vehicle. and the vehicle theft alarm was to deter them

 

[John Keith]

maxpower, there is nothing in this description that would preclude

Keep in mind that when you program one remote on this system you have to program all at the same time. Or it wipes out the ones that you didnt program.

This is the OP checking in. I've been following the discussion and I'm now at the point where I'm not sure I want to try the process for fear of ending up with no fob that works! My fobs do have identical Part # and FCC ID # for what that's worth (the vehciles were 1999 and 2000). And the process described in the owners manual gives the steps to program a different fob to work with the car but is silent about having to apply the process to the existing fob. I can't afford to have the dealer fix anything I screw up. Maybe I'll just continue using the low-tech key when I have to use my wife's car

John Keith

 

[Ted Mittelstaedt]

in this case, if you think about it,
the development costs of such systems are amortized over practically all new cars on the planet (I'm assuming the algorithms and chips all come from a handful of manufacturers), and the per-unit costs are probably not increased much at all.

Understandable, the problem is that this ALSO applies to things such as the human interface to the engine computer.

Why does it take a $10,000 scantool to interrogate the computer? Car computers today could be fitted with an USB port and you just plug in the laptop and run some software on it that interrogates the computer. Or better yet as I've said before, put an ethernet port on the car computer and put a webserver in it, and jack in your laptop running a web browser and use that to interrogate the computer.

IOW, there is some slight benefit overall,
but the cost is almost zero compared to a, say, pre-'96 system. It's not like some feel-good systems that are on our cars now or in the future from which the benefits are questionable but the added cost per vehicle is one or more hundreds of dollars.

Systems like the car computer interface which would cost almost zero due to amortization, yet deliver massive benefits, are not implemented. Systems like powered running boards that do nothing other than make the vehicle look like a rolling Christmas tree, ARE implemented. Is it any surprise Chrysler is this close to bankruptcy?

Ted

 

[Bill Putney]

Why does it take a $10,000 scantool to interrogate the computer? Car computers today could be fitted with an USB port and you just plug in the laptop and run some software on it that interrogates the computer. Or better yet as I've said before, put an ethernet port on the car computer and put a webserver in it, and jack in your laptop running a web browser and use that to interrogate the computer.

That's been available for years - I own a third party tool that plugs into the car's datalink connector and adapts to the USB port of a computer (typically a laptop) into which you load the tool's software (basically your computer and the software comprise the "tool").

Bill Putney
(To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')

 

[Ted Mittelstaedt]

That's been available for years - I own a third party tool that plugs into the car's datalink connector and adapts to the USB port of a computer (typically a laptop) into which you load the tool's software (basically your computer and the software comprise the "tool").

Yes, I know about those tools but that isn't what I'm talking about. The CPUs today used for embedded electronics like a vehicle car computer have plenty of extra power and the entire software that is in the tool could be easily stuck into the car computer - thus turning your laptop into nothing more than a human interface device, and alleviating the need to buy the software and the adapter that goes from the datalink connector to the USB port (which if you were to take it apart you probably would find quite a lot of intelligence in the adapter)

Remember, the software on the computer needs to read lots of different models of cars, so it's much larger than it would need to be if included in the car computer.

The federal government standardized the OBD-II connector over a decade ago, today there's much more common computer industry standard interfaces - ie: USB, firewire, and ethernet - where the controllers for these interfaces are much cheaper due to the fact that they aren't single-sourced. It's high time that the OBD-II interface be retired and replaced with one of these so you can just use an off-the-shelf $5 cable to plug your PC into the car computer.

Ted

 

[Ted Mittelstaedt]

You were able to do your older vehicles because it was not using the rolling code system I would think. when program a key fob into that year you didnt have to have all of them to reprogram. You were able to add one

No, in the older vehicles you have to program all the fobs in at the same time also. But the programming method is different, it involves grounding a wire and pushing buttons on the fobs, none of this business of requiring 2 working fobs beforehand. When I did it, I programmed the first vehicle then the second vehicle.

The older system only allows a max of 2 fobs to be programmed.

I'm also pretty sure it's a rolling key system, but I think it's a standard PRNG algorithm for all of the fobs.

Ted