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Discussion Starter · #1 ·
Before I get any smart commets, I know what the buttons do and how to start the car.:p

My question concerns the electronics inside the smart key for my 2002 CLK430.

I realize that the key uses both infared and RF, but when I start the car which is used?
It would seem the infared signal is used at some point durring the start up but is it used to turn the ignition on or just in the start position like in domestic vehicles?
If the infared is only used in the start position can any smart key turn the ignition on in my car?

Has anyone tried to manipulate the ignition circuitry for any mods?
 

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As far as I've understood correct from the experts, the key "in position" is using infrared for some purposes but then again, the actual theft protection would be RF ID type of communication, the car provides a radio carrier that both powers the RF ID chip and transfers data (challenge/response signalling to detect an allowed key) to the chip on the key, the chip transmits data through low power RF back to the car.

Then there is this higher power radio that operates door locks, this is different from the RF ID radio.

IR is also used for remote control of doors/windows/sun roof, through the IR receiver on the door handle.

Experts feel free to correct, references to detailed system descriptions welcome, I would be interested too.
 

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Discussion Starter · #4 ·
So The RF works the same as a domestic (ie. ford). Where, when the key is turned to the start position the RF signal is sent and recognized for starting purposes.

I guess I need to put some tape over the IR on the key and see what happens.
 

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Discussion Starter · #5 ·
Diesel Benz said:
What mods are you after? Remote starter?
Thats one of the mods I'm looking at.

I've read that it can't be done, but no one seems to be able to give me an exact reason why.

I hate when someone says, "it won't work" and can't give me a reason why it won't work or just gives a vague "it won't work because of the key.":mad:

What function of the key prevents me from doing a remote start?:confused:
Or any other ignition mod for that matter, such as moving the converable top and/or windows with a rain sensor or turning on the radio with a remote.

I have no problem with taking the whole dash out and chopping wire harnesses, but I don't want to waste the time if someone has already done it and can tell me exactly why I'm wasting my time.

When someone tells me something can't be done, I want to do it even more.

Thanks for your time and input Diesel
 

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worst mod in BW history
ML CLK Iridescent Hyundai Accent lol,GoPed Freightshaker & Volvo semi's, c'mawn?
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I've approached reputable installers about doing both remote or push button ignition and all of them said they wouldn't touch the job with a ten foot pole citing vague references as well. My only experience in regard to this is that I fried my ignition while doing some electrical work and foolishly leaving the key in and it was a costly dealer-only replacement. Be careful.
I don't see why you couldn't run secondary electronics to manipulate your rag top pump or stereo (assuming you bid a fond farewell to the Bose)
 

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Discussion Starter · #7 ·
ThrillKill said:
I've approached reputable installers about doing both remote or push button ignition and all of them said they wouldn't touch the job with a ten foot pole citing vague references as well. Be careful.
I've talked with two or three seasoned and certified installers whom I have worked with.
(none of which I would alow to touch the electronics of one of my vehicles. :p )

And as one of them so eloquently put it,
"I would rather dig out my eye with a spoon than work on your car."

Bottom line is they are scared of the unknown and only get paid for completed jobs.
Even more reason to show them who's boss.:bowdown:
I've installed more remote starts than I care to remember and have never been afraid of the unknown.
I may have been afraid after I saw it, but not before.

If it were only a transponder chip, the remote start would be in already.
I just don't want to take it apart more than once and I hate driving around with the dash apart while wating for parts.

Thats why I'm trying to unlock the mystique of this magical tool we call "The Smart Key."

When is the IR activated ?
How does the mechanical (inserting and turning the Key) corespond with the IR and RF?

Thanks for the concern.
 

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Don't all US cars have a smart key? In Europe this has been the case for years.

The idea of the smart key is that you cannot get the engine running if a genuine key is not present. You can force the starter motor run (provide power directly from the battery) but this would not make the engine fire. The idea is that the car gives a challenge number for the key, the key would know the correct response to this challenge and would send it to the car. From outside you cannot figure out the formula to calculate the correct answer even if you first know a correct challenge and response pair (this is a one-way formula typically used in cryptography).

In order to be able to start the engine, one would need to be able to give a proper answer to the challenge from the car. In order to do this, one would need to have the key functionality in the car, essentially equal to leaving your key to the car. A remote starter could then be a mechanical construction which shortly turns the key to start the engine. But who would want to leave the key to the car?

Even this would not work with keyless go where you would not be able to lock the doors if the key was in the car. If one would accept leaving the key to the car as long as the doors are locked, one certainly would not want to leave the key to the car and leave doors open.

To me this simply means that one would have to abandon security against car theft or abandon the remote starter option.

By the way, it was not clear from the video but I would assume that the key detection works with the RF ID even if the key battery was removed and the IR was not functional. The video gave the impression that IR communication is needed to make the engine start and run. Anybody tried to start the car with a key where batteries have been removed or the IR lens has been covered to disable the IR communication. My assumption is that the IR (and "high power RF") communications are convenience related (remote door opening/closing etc.) but the RF ID communication should work without the key battery, with the power from the electric field provided by the car and used for a power source for the RF ID (extremely low power operation on the RF ID). This is anyway how most other car types work with keys that have no battery (no IR or "high power" RF communication without a battery) and no IR eye at all. By "high power RF" I mean the radio signal that is able to reach the car from a distance of more than 10 metres. The RF ID radio communications signal power is intended to work over a distance of a couple of centimetres.
 

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Had a second thought on this. The video explains that the key gets energy inductively from the car, this is what I assumed too. The video also explains that the key authentication communications between the key and the car occurs through IR instead of low power RF as for RF ID, and as I assumed. The video must be right, the low range IR communications must be possible with the inductively provided power.

I also made a test. I shielded the IR eye with a thick piece of paper (allowing inductive power properly enter the key, this is why I did not use some metal folio). Now when I inserted the key, it did not even turn.

I should have removed the key batteries to be sure that inductively supplied power is sufficient for IR communications but I did not try that.

Raymond, thanks a lot for those informative videos.
 

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The correct answer to the "remote starter" question is the auxiliary heater as somewhere suggested but theoretically I guess one could take an old smart key, build an IR transceiver there, change the IR communication signal to an RF signal format, place a corresponding RF transceiver inside your home, change the data format back to IR for the key, and let your key "remotely" communicate with your car. You would still need a mechanical device turning the key but you would not need to leave the key to the car and no thief could steal your car.
 

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Discussion Starter · #15 ·
Diesel Benz said:
I also made a test. I shielded the IR eye with a thick piece of paper (allowing inductive power properly enter the key, this is why I did not use some metal folio). Now when I inserted the key, it did not even turn.
Thanks for the help, I didn't expect you would go and do experiments on your car.

So you've proven that the IR signal act as the "toothed key" for any other vehicle and we know it also unlocks the steering wheel.

The next question is does the IR turn off the immobilizer or is that done by RF when the key is turned to the start position?

So far this hasn't discouraged me from anything.:)

It sounds like any other car were a portion of a third coded key must be taken apart and wired into the dash where it can't be easily found or used if it were found. ( ie, on a ford you would take the RF key cut off the part you would insert into the ignition and only wire the transponder into the dash)

Now if the IR is used to turn off the immobilizer that could be interesting but still do able?
Any thoughts on this?

Another question, does anyone know if the actual ignition wires (i.e. accessory, ignition, start and some 12v power) are connected to the key mechanism or is there a brain unit somewhere connected by data cables?

Raymond, thanks for the great vids.:bowdown:
I tried to look at the site but none of the pics showed up.
You don't have a schematic of the wiring behind the key mech do you?
 

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Discussion Starter · #16 ·
Diesel Benz said:
The correct answer to the "remote starter" question is the auxiliary heater.
Here in on the Mississippi Gulf Coast, the yearly low temp is around 40 degrees (F) and that only happens for around 20 days a year.
I think it snowed last in 1994 and it was measured in flakes not inches.
It is nice to be able to heat the car a few days a year but the main use for a remote start here is to cool the car on one of the many above 100 degree days so you don't burn your legs on the hot leather seats. :p

Diesel Benz said:
theoretically I guess one could take an old smart key, build an IR transceiver there, change the IR communication signal to an RF signal format, place a corresponding RF transceiver inside your home, change the data format back to IR for the key, and let your key "remotely" communicate with your car. You would still need a mechanical device turning the key but you would not need to leave the key to the car and no thief could steal your car.
I like your thinking but hopefully I wouldn't have to take it that far and definatly no mechanical devices.

Thanks again!
 

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Cujonutti said:
Here in on the Mississippi Gulf Coast, the yearly low temp is around 40 degrees (F) and that only happens for around 20 days a year.
I think it snowed last in 1994 and it was measured in flakes not inches.
It is nice to be able to heat the car a few days a year but the main use for a remote start here is to cool the car on one of the many above 100 degree days so you don't burn your legs on the hot leather seats. :p
Thanks again!
I see, didn't take into account you were from South. In order not to completely lose my face, I have to try something ;-) That is, the auxiliary heater is still good for you, in hot weather if you start the auxiliary heater, instead of starting to warm up the car, it switches the heater blower on, thus cooling the car. Of course this does not work further than reducing the car temperature close to that of the external temperature.

There was an option for the E-class at least where fans were driven by solar energy. What I'm after is that the remote starter is not very environmentally friendly, where you use it to cool the car or to warm it up. At least in your case it does not harm the engine as much as when warming up the car.

And I like your motto, people should be allowed to tell their opinions but everybody should be allowed to decide for him/herself what suits best. If one wants to turn the other ones head, a good "why not" is a lot better than a simple "no way".
 

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Discussion Starter · #18 ·
Diesel Benz said:
What I'm after is that the remote starter is not very environmentally friendly, where you use it to cool the car or to warm it up. At least in your case it does not harm the engine as much as when warming up the car.
Point taken:thumbsup:

Diesel Benz said:
And I like your motto, people should be allowed to tell their opinions but everybody should be allowed to decide for him/herself what suits best. If one wants to turn the other ones head, a good "why not" is a lot better than a simple "no way".
I like to think I have an open mind to others opinions :surrender: ,but have seen threads like this turn into an argument where people are screaming "Give it up, It can't be done" without the first factual or technical explanation.
I didn't want this to be one of them.

Thanks
 
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