PT Cruiser key question

On Mon, 26 Oct 2009 07:08:46 -0700 (PDT), "Pete E. Kruzer"
> wrote:

>Is the battery replaceable? How long will the Sentry Key work? My 2001
>Cruiser uses one.
>When I first got it, I went to Sears and had four keys made, for the
>wife and daughters and
>a spare for the wallet when I locked the keys in the car.
>Then when I found out they wouldn't start the car, I threw them out.
>After they were in a landfill
>I realized that they would open the door and hatch so the one in the
>wallet would have sufficed.

What I do is get a transponder key and hide it inside the vehicle and
a non-transponder key and hide it outside the vehicle. If I lock my
keys in I can get in. If I lose my keys I can get in and then get the
other key and start it. If anyone finds my non-transponder key they
will be able to open the door but not start the car. Most likely
having found a key they are not likely to realize they need to
continue hunting for a second key.

On Mon, 26 Oct 2009 19:34:33 -0400, wwilson
> wrote:

>The responder has two batteries in series. I have replaced mine for a
>2001 PT. They cost about $4 apiece at my local battery source.
>


The batteries are for the RKE. The TRANSPONDER is energized by the
halo around the iginition cylinder.

On Mon, 26 Oct 2009 08:40:27 -0400, Steve Stone >
wrote:

>Ashton Crusher wrote:
>> On Sun, 25 Oct 2009 16:49:54 -0400, Steve Stone >
>> wrote:
>
>> I think it's the same blank and transponder for them. I don't see why
>> you could not reuse it as a transponder. But the teeth are not likely
>> going to match your new car if that's what you mean by "cut the same".
>
>I see there are eBay vendors selling blanks where you supply the
>transponder.
>Why can't the transponder be recoded?

Because they were designed that way. Trying to program a key that's
already programmed to another vehicle will fail. Probably security
reasons.

>Only excuse I can see for that is a need for dealers to suck another
>$200 from my wallet.

Dealers don't design these systems. Go whine to the engineers.

>There sure isn't much inside. a single surface mount IC, a coil/antenna,
>and a button battery.

On Mon, 26 Oct 2009 22:00:10 -0400, "Wesley" > wrote:

>Is the transponder (key) programmed for the vehicle, or is the vehicle
>programmed to recognize the transponder? It would seem to me that the car
>would be more easily reprogrammed than the "key"... Not that the system
>designers would necessarily think the same way I do of course...!
>
>Wesley

Both are true. The key is programmed with info from the vehicle, and
the vehicle is programmed with the key's ID.

The key's ID can be erased from the vehicle, but once programmed, the
key cannot be reprogrammed to another vehicle.

>
>
>"Ashton Crusher" > wrote in message
.. .
>
>> I think it's the same blank and transponder for them. I don't see why
>> you could not reuse it as a transponder. But the teeth are not likely
>> going to match your new car if that's what you mean by "cut the same".
>

On Mon, 26 Oct 2009 20:17:11 -0700, Ashton Crusher >
wrote:

>TO the best of my knowledge the key transponder is just a transponder
>and isn't "programmed", all the programming is done on the car's
>computer. Typically they can accept up to 8 transponder codes.
>

The key does get programmed with info from the vehicle.

On Tue, 27 Oct 2009 00:06:59 -0400, bllsht >
wrote:

> On Mon, 26 Oct 2009 19:34:33 -0400, wwilson
> > wrote:
>
>> The responder has two batteries in series. I have replaced mine for a
>> 2001 PT. They cost about $4 apiece at my local battery source.
>>
>
>
> The batteries are for the RKE. The TRANSPONDER is energized by the
> halo around the iginition cylinder.
>

Thanks for the explalnation. I didn't realize the two parts differed with
respect to needing batteries.

--
Using Opera's revolutionary e-mail client: http://www.opera.com/mail/

bllsht wrote:
> On Mon, 26 Oct 2009 08:40:27 -0400, Steve Stone >
> wrote:
>
>> Ashton Crusher wrote:
>>> On Sun, 25 Oct 2009 16:49:54 -0400, Steve Stone >
>>> wrote:
>>> I think it's the same blank and transponder for them. I don't see why
>>> you could not reuse it as a transponder. But the teeth are not likely
>>> going to match your new car if that's what you mean by "cut the same".
>> I see there are eBay vendors selling blanks where you supply the
>> transponder.
>> Why can't the transponder be recoded?
>
> Because they were designed that way. Trying to program a key that's
> already programmed to another vehicle will fail. Probably security
> reasons.

That's not true for the Chrysler Sentry Keys, which are manufactured by
Strattec for Chrysler. You can program as many cars to a single key as
you wish. However it wouldn't make a lot of sense to do that if you
want to cut the key and use it, since every car (should) have a
different cut. But you could hold up a programmed uncut key near the
ignition switch while you used a non-Sentry key to start the car.

That's one way to get a cheaper remote starter to work--just place a
programmed Sentry Key inside the steering column. But it also
eliminates all security benefits of the Sentry Key.

You can only program eight keys to one car.

>> Only excuse I can see for that is a need for dealers to suck another
>> $200 from my wallet.
>
> Dealers don't design these systems. Go whine to the engineers.

Engineers don't set the retail price, dealers do. The Chrysler Sentry
keys are often obtained at a much lower price than the dealership sells
them for from local locksmiths, etc. Try www.amazingkeys.com or even
ebay.

G

On Mon, 26 Oct 2009 21:37:57 -0700, bllsht
> wrote:

>On Mon, 26 Oct 2009 22:00:10 -0400, "Wesley" > wrote:
>
>>Is the transponder (key) programmed for the vehicle, or is the vehicle
>>programmed to recognize the transponder? It would seem to me that the car
>>would be more easily reprogrammed than the "key"... Not that the system
>>designers would necessarily think the same way I do of course...!
>>
>>Wesley
>
>Both are true. The key is programmed with info from the vehicle, and
>the vehicle is programmed with the key's ID.
>
>The key's ID can be erased from the vehicle, but once programmed, the
>key cannot be reprogrammed to another vehicle.
>

What would be the point? I fail to see the logic of it. I'm not
saying you are wrong.

Ashton Crusher > writes:

> On Mon, 26 Oct 2009 21:37:57 -0700, bllsht
> > wrote:
>
>>On Mon, 26 Oct 2009 22:00:10 -0400, "Wesley" > wrote:
>>
>>>Is the transponder (key) programmed for the vehicle, or is the vehicle
>>>programmed to recognize the transponder? It would seem to me that the car
>>>would be more easily reprogrammed than the "key"... Not that the system
>>>designers would necessarily think the same way I do of course...!
>>>
>>>Wesley
>>
>>Both are true. The key is programmed with info from the vehicle, and
>>the vehicle is programmed with the key's ID.
>>
>>The key's ID can be erased from the vehicle, but once programmed, the
>>key cannot be reprogrammed to another vehicle.
>>
>
> What would be the point? I fail to see the logic of it. I'm not
> saying you are wrong.

I don't know the technology used in those keys, but there are lots of
write-once memory technologies: they come from the foundry with all the
bits set to 1 (or 0); you can write any bit you want to the other state,
but once written you can't change it back. So you can set a code by
setting a bunch of 1's, and you can wipe the code by setting all the
other 1's. But you can't set a new code.

The clearest example is the original PROM (which is completely obsolete,
but still a good example): comes programmed with all 0's. You set a 1
by putting a big enough current through a junction to quite literally
blow a tiny fuse. Once you've done that you can't set it back to a 0.
--
As we enjoy great advantages from the inventions of others, we should
be glad of an opportunity to serve others by any invention of ours;
and this we should do freely and generously. (Benjamin Franklin)

On Tue, 27 Oct 2009 22:38:51 -0400, Greg Houston >
wrote:

>bllsht wrote:
>> On Mon, 26 Oct 2009 08:40:27 -0400, Steve Stone >
>> wrote:
>>
>>> Ashton Crusher wrote:
>>>> On Sun, 25 Oct 2009 16:49:54 -0400, Steve Stone >
>>>> wrote:
>>>> I think it's the same blank and transponder for them. I don't see why
>>>> you could not reuse it as a transponder. But the teeth are not likely
>>>> going to match your new car if that's what you mean by "cut the same".
>>> I see there are eBay vendors selling blanks where you supply the
>>> transponder.
>>> Why can't the transponder be recoded?
>>
>> Because they were designed that way. Trying to program a key that's
>> already programmed to another vehicle will fail. Probably security
>> reasons.
>
>That's not true for the Chrysler Sentry Keys, which are manufactured by
>Strattec for Chrysler. You can program as many cars to a single key as
>you wish. However it wouldn't make a lot of sense to do that if you
>want to cut the key and use it, since every car (should) have a
>different cut. But you could hold up a programmed uncut key near the
>ignition switch while you used a non-Sentry key to start the car.

I don't know where you got that information, but it's wrong. A key
can only be programmed to one vehicle. The sentry key can only store
the information from one module, and that info cannot be changed once
it has been programmed.

>
>That's one way to get a cheaper remote starter to work--just place a
>programmed Sentry Key inside the steering column. But it also
>eliminates all security benefits of the Sentry Key.
>
>You can only program eight keys to one car.
>
>>> Only excuse I can see for that is a need for dealers to suck another
>>> $200 from my wallet.
>>
>> Dealers don't design these systems. Go whine to the engineers.
>
>Engineers don't set the retail price, dealers do. The Chrysler Sentry
>keys are often obtained at a much lower price than the dealership sells
>them for from local locksmiths, etc. Try www.amazingkeys.com or even
>ebay.
>
>G

Dealers don't prevent changing the info stored in the key, which is
what the OP was whining about.