Let's discuss the key fob transponder chip(s)
Join Date: Nov 2017
Location: Alexandria, Kentucky
Age: 85
Posts: 521
Likes: 0
Received 18 Likes
on
13 Posts
Re: Let's discuss the key fob transponder chip(s)
Gentlemen - The original question still remains unanswered. See "Red Dog's" original question about the chips in his first posting on this subject. Does anyone have an answer for him, or the rest of us?
Someone else asked I believe it was CL770, in reply # 8, if anyone has used the new transponder chips listed on ebay and the tool that is also listed for programming them. I can't see that anyone answered that question either. Does anyone have an answer?
I'm not being super critical, just wondering if anyone has any answer's to these questions.
Jim
"
Someone else asked I believe it was CL770, in reply # 8, if anyone has used the new transponder chips listed on ebay and the tool that is also listed for programming them. I can't see that anyone answered that question either. Does anyone have an answer?
I'm not being super critical, just wondering if anyone has any answer's to these questions.
Jim
"
Re: Let's discuss the key fob transponder chip(s)
I listed this information because this is what I use and it works fine for me!
I'm also looking at the SKREEM modules with another forum member and I'd like to know from someone who has had a SKREEM failure if the no start issue effects all the keys for the car or just one key? If someone can tell me this it would narrow the failure down a bit.
I'm also looking at the SKREEM modules with another forum member and I'd like to know from someone who has had a SKREEM failure if the no start issue effects all the keys for the car or just one key? If someone can tell me this it would narrow the failure down a bit.
Join Date: Nov 2017
Location: Alexandria, Kentucky
Age: 85
Posts: 521
Likes: 0
Received 18 Likes
on
13 Posts
Join Date: Jun 2009
Location: Fort Worth, Texas
Age: 64
Posts: 13,569
Received 965 Likes
on
752 Posts
Re: Let's discuss the key fob transponder chip(s)
There have been many failures and both keys fail to start the car.
Re: Let's discuss the key fob transponder chip(s)
What I would like to know is if the circuit board inside the fob can be used universally, most posts on this subject say it cannot. If not why not?
Surely that would mean another level of security which would be overkill in my mind, but there again I am not a German engineer making life difficult for the masses.
Is it capable of transmitting and receiving signals at a distance or does it receive only when in close proximity to the halo.
If we would like to fabricate keys from scratch using old circuit boards with new chips, keys and cases we need to know this or we will not be able to do it.
Surely that would mean another level of security which would be overkill in my mind, but there again I am not a German engineer making life difficult for the masses.
Is it capable of transmitting and receiving signals at a distance or does it receive only when in close proximity to the halo.
If we would like to fabricate keys from scratch using old circuit boards with new chips, keys and cases we need to know this or we will not be able to do it.
Join Date: Nov 2017
Location: Alexandria, Kentucky
Age: 85
Posts: 521
Likes: 0
Received 18 Likes
on
13 Posts
Re: Let's discuss the key fob transponder chip(s)
180 - Very good question about boards being universal and why not. I agree with you that if these circuit boards are VIN sensitive, that would be "overkill". Any way we can find out? My understanding, right or wrong, is that the boards are for locking and unlocking and for the panic alarm, and that the chip is for starting the car. I thought the circuit board was to send a signal to the chip, to the SKREEM and then allowed the ignition to start the car.
Jim
Jim
Join Date: Jul 2009
Location: Central South Carolina
Age: 69
Posts: 5,997
Received 503 Likes
on
429 Posts
Re: Let's discuss the key fob transponder chip(s)
180 - Very good question about boards being universal and why not. I agree with you that if these circuit boards are VIN sensitive, that would be "overkill". Any way we can find out? My understanding, right or wrong, is that the boards are for locking and unlocking and for the panic alarm, and that the chip is for starting the car. I thought the circuit board was to send a signal to the chip, to the SKREEM and then allowed the ignition to start the car.
Jim
Jim
Hi Jim, the circuit board is ONLY for the lock/unlock/panic. The TRANSPONDER in the FOB is to allow the ring to pick up signal and allow the car to start through the SKREEM.
.
Re: Let's discuss the key fob transponder chip(s)
180 - Very good question about boards being universal and why not. I agree with you that if these circuit boards are VIN sensitive, that would be "overkill". Any way we can find out? My understanding, right or wrong, is that the boards are for locking and unlocking and for the panic alarm, and that the chip is for starting the car. I thought the circuit board was to send a signal to the chip, to the SKREEM and then allowed the ignition to start the car.
Jim
Jim
Then, try to lock/unlock the doors with YOUR fob; if it works, it is a universal circuit board.
(Don't forget to reprogram his SKREEM to match his fob after the test)
This test would be like reprogramming the SKREEM to match the fob after a battery disconnect.
If someone tries this test let us know the results.
Would try this myself if another Crossfire was available.
The transponder chip in the fob is another matter to deal with.
Cheers,
Re: Let's discuss the key fob transponder chip(s)
Want to see if the circuit board is universal?Go to a buddy's Crossfire and double click YOUR fob, then have him turn on the ignition with HIS key fob.
Then, try to lock/unlock the doors with YOUR fob; if it works, it is a universal circuit board.
(Don't forget to reprogram his SKREEM to match his fob after the test)
This test would be like reprogramming the SKREEM to match the fob after a battery disconnect.
If someone tries this test let us know the results.
Would try this myself if another Crossfire was available.
The transponder chip in the fob is another matter to deal with.
Cheers,
Then, try to lock/unlock the doors with YOUR fob; if it works, it is a universal circuit board.
(Don't forget to reprogram his SKREEM to match his fob after the test)
This test would be like reprogramming the SKREEM to match the fob after a battery disconnect.
If someone tries this test let us know the results.
Would try this myself if another Crossfire was available.
The transponder chip in the fob is another matter to deal with.
Cheers,
To test you would need to use your circuit board in place of his board and then go through the sync process. You could lose a friend if you screwed up his SKREEM.😉
Join Date: Nov 2017
Location: Alexandria, Kentucky
Age: 85
Posts: 521
Likes: 0
Received 18 Likes
on
13 Posts
Re: Let's discuss the key fob transponder chip(s)
Chooch - 180 - Hope there is an easier way to find out if they are universal. I don't have a friend with a Crossfire, so that rules me out. I hope someone on the forum has a way find out the answer. I wouldn't want to mess up ANYONE's SKREEM module. Maybe someone that has two Crossfire's in their family.
Jim
Jim
Join Date: Jun 2009
Location: Fort Worth, Texas
Age: 64
Posts: 13,569
Received 965 Likes
on
752 Posts
Re: Let's discuss the key fob transponder chip(s)
C'mon you guys. The FOB board is NOT VIN-specific, and we all know that - you can buy generic FOBs off eBay, transplant the RFID chip and the blade from the old FOB, insert it, hit a button twice - and you are good to go.
We have all known this for YEARS.
And even if you didn't already know this - "rolling code" would be your first clue that the FOB board is generic.
We have all known this for YEARS.
And even if you didn't already know this - "rolling code" would be your first clue that the FOB board is generic.
Join Date: Jun 2009
Location: Fort Worth, Texas
Age: 64
Posts: 13,569
Received 965 Likes
on
752 Posts
Re: Let's discuss the key fob transponder chip(s)
What I would like to know is if the circuit board inside the fob can be used universally, most posts on this subject say it cannot. If not why not?
Surely that would mean another level of security which would be overkill in my mind, but there again I am not a German engineer making life difficult for the masses.
Is it capable of transmitting and receiving signals at a distance or does it receive only when in close proximity to the halo.
If we would like to fabricate keys from scratch using old circuit boards with new chips, keys and cases we need to know this or we will not be able to do it.
Surely that would mean another level of security which would be overkill in my mind, but there again I am not a German engineer making life difficult for the masses.
Is it capable of transmitting and receiving signals at a distance or does it receive only when in close proximity to the halo.
If we would like to fabricate keys from scratch using old circuit boards with new chips, keys and cases we need to know this or we will not be able to do it.
Is it capable of transmitting and receiving signals at a distance or does it receive only when in close proximity to the halo.
Not the Halo - close proximity to the antenna, behind the Speedometer/Tachometer.
Its in the service manual diagrams, look under "wiring" then "Connector pinouts".
- The HALO is used to energize and communicate with the RFID chip. (Pins 1 and 2 of C3 on the SKREEM are the 'hot' and 'shield' going to the Halo, shielded coax is used to prevent the signal from radiating outside the ring, more on that below.)
- The rolling code lock/unlock board communicates with the SKREEM with the antenna wire in the harness of the SKREEM. (Pin 6 of C1 [C1 is the main SKREEM connector, that dead-end wire on pin 6 is the antenna.])
Some RF basics here:
The halo is not so much an antenna but a coil.
Antennas are intended to radiate. And the antenna on the SKREEM does that, it also is capable of intercepting signals - and it does that, too. When you press a button, your FOB transmits, the SKREEM hears it and IT transmits back, "rolling the code" in the FOB.
The "halo" (coil) is intended to radiate RF energy as well, but it is designed to contain that radiation largely in the area inside it's circumference. This is for two reasons:
- We need a considerable amount of energy directed to the RFID chip, we need this because this RF is the ONLY source of power for the RFID chip to use to transmit back. When the RFID chip receives this power, it uses it to generate it's signal with the secret code the SKREEM is looking for. So we contain the RF in that small area it is needed in.
- We do not want the signal from the SKREEM or the response from the RFID chip to be detectable to anyone trying to listen to record the code, that would defeat the purpose of the RFID chip in the first place. So again, we use a coil to contain the signal.
35 years in RF (radio) here. The things I do not know could fill volumes of books - but I better know RF by now.
Last edited by pizzaguy; 12-16-2018 at 10:56 PM.
Re: Let's discuss the key fob transponder chip(s)
Your plan has a large fault, the key has to be in the ignition and turned to enable the synchronization of the door Lock/Unlock programming. If the key does not fit then you cannot do this. Fitting his key will not work either as I assume the fob has the wrong chip in it.
To test you would need to use your circuit board in place of his board and then go through the sync process. You could lose a friend if you screwed up his SKREEM.😉
Originally the main purpose of this thread was to address the key fob transponder chips, but it expanded to cover the fob's Remote Keyless Entry (RKE) transmitter circuit board function with regard to controlling the central locking system.
The fob's RKE circuit board must be synchronized with the SKREEM using a rolling code to lock/unlock doors or set panic alarm.
- The key does not have to be in the ignition switch for the fob circuit board to transmit to the SKREEM. It communicates at distance via RF signal when the lock/unlock buttons are pressed.
- To resynchronize the SKREEM's lock/unlock function with the RKE transmitter circuit board:
- Press one of the fob buttons momentarily twice.
- Then turn the key in the ignition switch to the ON/RUN position within 30 seconds.
- Turning the ignition switch to ON/RUN powers up the SKREEM's antenna to query the key's chip for validity.
- With a valid chip in the antenna ring, the SKREEM synchronizes with the last RKE transmitter code received in the past 30 second
Or, I missed something along the line ... thoughts?
Join Date: Jun 2009
Location: Fort Worth, Texas
Age: 64
Posts: 13,569
Received 965 Likes
on
752 Posts
Re: Let's discuss the key fob transponder chip(s)
There are TWO ways of syncing the FOB.
- Your way.
- The owner's manual way: Put the key in the ignition, turn to "ON" and hit either button twice.
I do remember reading about your way - that comes from the student reference, doesn't it?
Re: Let's discuss the key fob transponder chip(s)
You got it!
There are TWO ways of syncing the FOB.
I do remember reading about your way - that comes from the student reference, doesn't it?
There are TWO ways of syncing the FOB.
- Your way.
- The owner's manual way: Put the key in the ignition, turn to "ON" and hit either button twice.
I do remember reading about your way - that comes from the student reference, doesn't it?
Re: Let's discuss the key fob transponder chip(s)
It's hard trying to nail down what is actually going on with the RKE, SKREEM, PCM, BCM, and Central Locking System.
They are all interrelated to some extent and not much documentation.
Also, along the reading, I found that the FOB RKE has a range of 20 meters (66 feet), that's a pretty good distance from the halo.
But I don't think the halo is the RKE's receive antenna.
When I replaced my SKREEM, there was a second 2-wire connector next to the halo connector that looked like its twin. I'm betting that the leads went to the RKE receive antenna.
Wish I had traced it out when I had the dash out...
BTW: Although I'm a newbie (got my Crossfire in SEP '18), I did spend quite a few years as a Systems Engineer and Software Engineer before turning Educator (Not much software work in Pensacola, but a lot of Training/Education opportunities and there is the sugar white sands at the beach.)
Also, wish 35 years in radio under your belt I'll bet you know the world of Pentodes, Triodes, Diodes and solid state components (Npn, pnp) etc. that I started out with.
HAM License KR4BY
Are we having fun, yet?
Join Date: Jun 2009
Location: Fort Worth, Texas
Age: 64
Posts: 13,569
Received 965 Likes
on
752 Posts
Join Date: Jun 2009
Location: Fort Worth, Texas
Age: 64
Posts: 13,569
Received 965 Likes
on
752 Posts