Re: remote entry -key fob programming

"Bill Putney" <bptn@[EMAIL PROTECTED]
> wrote in message
news:5ugobdF1hli1fU1@[EMAIL PROTECTED]
> MoPar Man wrote:
> > maxpower wrote:
> >
> >>> I have a 1999 Plymouth Voyager and my wife has a 2000 Dodge
> >>> Caravan.  Is it possible to program my key fob so that it will
> >>> also open my wife's car?
> >> No
> >
> > It's not the fob that's programmed.  It's the computer in the vehicle.
>
> Though you might be right, that seems counterintuitive.
>
> I have two 2nd gen. LH cars sitting in my driveway that use fobs of the
> same part number.  If I took the fob of car no. 1 and followed the
> programing procedure using car no. 2 and its fob, then both fobs would
> control car no. 2, and car no. 1 would no longer respond to either.  If
> what you're saying is true (that it is the car's computer that gets
> programed), that doesn't sound possible.  Or would in fact both cars
> respond to what was car no. 1's fob after the reprograming?
>
> Bill Putney
> (To reply by e-mail, replace the last letter of the alphabet in my
> address with the letter 'x')

The RKE system and transmitter use a rolling code method for transmitting
the information . Rolling code is a method used to provide extra security
to
a transmitted signal. The transmitter sends a randomly selected sequence
code each time a signal is sent. The code increments vary depending on a
unique algorithm that is preprogrammed to each transmitter at the time it
was built. The sequence changes each time the transmitter is used. ( If a
scanner is used to try to pick the signal up it can not be duplicated)
because the sequence code cannot be calculated from the encoded
transmission. The receiver module also learns the transmitter id code and
initial sequence code at the time of transmitter programming. The receiver
then expects the next transmitted sequence code to increment within a
predetermined range of numbers
Each Transmitter has its own code and the code is programmed and stored
into
the receiver memory. The newer key fobs transmit a unique rolling  code id
message to the RKE module. Transmitters and receivers are unique to each
vehicle line and will not work.