something that has me scared

[ASmartMan]

As we all have read the Uk thread, a common problem is the remote losing its mind (not working to open the door).

I have taken on the project to identify the parts (with an accompanying schematic) for the TX and see if I can find the code (for my car).

In the UK this can be fixed (for a cost) BUT here in the US we are out in the cold (refusal of MB to support us). All parts in the TX are identified, I will use a spectrum analyzer to nail down the signature of my TX, NOW whether I can reproduce it it another story.

If I am able to pull this off (reading the code) and being able to write the code to a defunct key/new key, I would be willing io do this (for the cost of shipping) for my fellow USA 450 owners (I would need a working key and a defunct/new key to do this.

Don't make any plans JUST yet I just finished doing a photographic detail of the IC in the key ring, http://www.putfile.com/album/0/afineman I still have to pach them together to make sense of the circuits, SSSOOO don't hold your breath

ASM

[Carnut]

450 or 451?

[ASmartMan]

Carnut

I own a 450 and all the problems in the UK forum have been with the 450, it may be too soon to see if it is a problem with the 451 too.

Because I have never seen a 451 key (or its guts), I'll only be posting about my 450 key/transmitter and what (if anything) I find to resolve this problem.

Maybe what I find (if anything) may be transferable to the 451 key, but that will be for a 451 geek to follow through on.

Sorry for the non help

ASM

[24-42]

Originally Posted by Carnut

450 or 451?

HE SAID 450 !

[ASmartMan]

For those who want to follow along

PDF of IC #1 http://www.atmel.com/dyn/resources/p...ts/doc4591.pdf

This is the heart of the remote, all the rest of the parts are resisters, caps, Xtal (I think) and a transistor (for transmission).

This will be a timely project, so if anyone else wants to jump in (collaboration) your help would be welcome, OOOHHH and also if any one has a dead key (I'm using my working key as the test bed) and would be willing to donate it to this project, I would welcome that donation.

ASM

[Evilution]

I can't calaborate but I can save you a lot of time. Don't bother!

The code that comes from the key is a rolling code meaning it changes every time, it uses an encrypted algorythm to decide the next code which can be one of over 100 million combinations.

The key isn't coded to work with the car, the car is coded to work with the key. If you cloned your key and even managed to decypher the algorythm so it used the correct code each time, using it would just put the other key out of sync.

If you want to code your car to a new key, you have to by MB-star and a multiplexer costing about $2000 and then get the TAN code from smart gmbh which you can use once to code the car.

The good thing is that this system can add other TAN codes too as long as smart gmbh will supply them. MB-star works on the 451 as well.
You could add paddle shift codes to both styles, cruise control to a 450 etc.

[Amethyste]

Originally Posted by 24-42

HE SAID 450 !

Woah!? A tad touchy?

[Carnut]

Originally Posted by 24-42

HE SAID 450 !

I was just checking. You my friend have a big 450 chip on your shoulder!

[ASmartMan]

Kane

SURE, THANKS, stick a pin in my balloon. BUT we Gray owners NEED to figure something out.

IF anyone of us, loses our ability to unlock/reset the immobilizer we are in deep DO DO.

I'll still document the key electronics, figuring maybe some day it may come in handy to someone.

SSOO now my quest will be to find where the signal goes into the computer (or are you going to burst that one too and tell me the decode chip is on the ECU).

Some where there is a "1" or a "0" that does this, maybe if I check some underground sources I can find application noter or even a schematic for the ECU.

OOHH still if anyone has a dead key, I will pay postage to have it sent to me so I can do a destructive test to get the schematic accurate.

ASM

ps. Kane, even thought you just killed my project, I want to thank you for your input, this will of saved me MANY hours of failure, allowing me to focus/try something eles, thanks for adding your insight.

Brent

[Yellowcarsrock]

"The code that comes from the key is a rolling code meaning it changes every time, it uses an encrypted algorythm to decide the next code which can be one of over 100 million combinations."

So Evilution,
If this is the case and you have a spare key, how would the spare know what code was set between the other key and the car? Would the spare just be useless?
Also, if you unlock the door using the key hole under the door handle would you still not be able to drive the car due to an "immoblizer"?
Still waiting for my 451 to arrive. I'm a 1200.