Wireless keys blanks

In article >, MoPar Man >
wrote:

> aarcuda69062 wrote:
>
> > My service information states that the rolling code is between the
> > SKREEM and the PCM on the PCI bus.
> >
> > The SKREEM reads the RFI chip in the SKIM key, the SKREEM also has a
> > secret code programmed in it that the SKIM key has to recognize to
> > enable a valid start sequence.
>
> That doesn't sound like rolling code.

What (of my 2 above paragraphs) doesn't sound like rolling code?

> That sounds more like this:
>
> -------------------
> Cryptographic Electronic Code
>
> The transponder memory is protected using bi-directional encryption of
> data. Internal algorithms are configured to interpret the messages sent
> from transponder to ECU. This is similar to password protection.
> ------------------
>
> For both fixed and rolling code key systems, the key does not recieve
> any signal from the car's computer. It only transmits a code. It's a
> uni-directional system (key -> car). In theory, both a fixed key and
> rolling code key could be used on 2 different cars (naturally with
> exactly the same physical key-cut).
>
> With cryptographic keys, there is bi-directional data transfer (key <->
> car) and this would allow a key to be coded to a specific car.
>
> Which chrysler vehicles have this Cryptographic code system?

You should ask at that web site that you're considering to be a better
authority on the subject than Chrysler.

aarcuda69062 wrote:

> > > My service information states that the rolling code is between the
> > > SKREEM and the PCM on the PCI bus.
> > >
> > > The SKREEM reads the RFI chip in the SKIM key, the SKREEM also has
> > > a secret code programmed in it that the SKIM key has to recognize
> > > to enable a valid start sequence.
> >
> > That doesn't sound like rolling code.
>
> What (of my 2 above paragraphs) doesn't sound like rolling code?

The fact that there *may be* "rolling code" between the SKREEM and the
PCM is irrelavent (and a curiosity).

It's the communication between the Key and the SKREEM that we're talking
about.

Read this:

-----------------
OPERATION

Each Sentry Key has a unique transponder identification code permanently
programmed into it by the manufacturer. Likewise, the Sentry Key Remote
Entry Module (SKREEM) has a unique "Secret Key" code programmed into it
by the manufacturer as well. When a Sentry Key is programmed into the
memory of the SKREEM, the SKREEM stores the transponder identification
code from the Sentry Key, and the Sentry Key learns the "Secret Key"
code from the SKREEM. Once the Sentry Key learns the "Secret Key" code
of the SKREEM, it is also permanently programmed into the transponder's
memory. Therefore, blank keys for the Sentry Key Remote Entry System
(SKREES) must be programmed by the SKREEM in addition to being cut to
match the mechanical coding of the ignition lock cylinder. Refer to
Electrical, Vehicle Theft Security, Transponder Key, Standard Procedure
- Transponder Programming.

The Sentry Key's transponder is within the range of the SKREEM's
transceiver antenna ring when it is inserted into the ignition lock
cylinder. When the ignition switch is turned to the ON position, the
SKREEM communicates with the Sentry Key via a radio frequency (RF)
signal. The SKREEM determines if a valid key is present based on the
information it receives from the Sentry Key. If a valid key is detected,
that fact is communicated to the PCM via the PCI bus and the vehicle is
allowed to continue running. If an invalid key is received by the PCM or
no status at all is communicated, the vehicle will stall after two (2)
seconds of running. The indicator light will be flashing at this point.
The Sentry Key's transponder can not be repaired. If it is faulty or
damaged, it must be replaced.
-----------------

-> The SKREEM has a unique code which is sent to the key

-> The key must initially learn the SKREEM's code. No idea if
a key can learn more than 1 SKREEM code.

-> The key has it's own code, which the SKREEM must initially learn.

-> In use, the SKREEM and KEY exchange codes. Seems that the SKREEM
transmits it's code first. No idea why the key needs to know the
SKREEM's code. I don't know what situation the designers were
imagining such that they wanted the key to respond to a code
transmitted by the SKREEM.

Rolling code implies that the code numbers are not static, but that they
change based on an algorythm known to the receiver. All the
descriptions of bi-directional code transfers I've read so far between
keys and SKREEM modules use static codes - not rolling codes.

And my question still stands: What make and model year vehicles have
transmit-only key transponders, and which have bi-directional key
transponders?

"NotMe"

|I have an 04 Mini Van with wireless locks and electric doors. I need to
| replace one of the keys and am getting all sorts of confusing info and
| prices.
|
| Where can I find reasonable prices and reliable equipment. One vendor
will
| sell me OEM keys but I have to take to someone to have them programmed.
| Others will sell me the keys for one price and the instructions for
| programming for another.
|

Problem solved!!!

Seem a good friend of my one of my grand kids is dating the kid of someone
with connections @ Chrysler.

Key was replaced with an OEM for ~$15 plus tax which is a h*ll of alot
better then the $175 to $185+ I've been getting

Thanks for all the input.