Mercedes-Benz Forum banner

1 - 13 of 13 Posts

·
Registered
1998 ml-320 stock,oem bug deflector, nerf bars, leather gray upholstery, delivery date 25 nov 97
Joined
·
677 Posts
Discussion Starter #1
i just read this posting


If you had the key in the ignition while being jump started or the battery replaced, the key has been fried (dead).

does this mean don't have key in switch while hooking up jumper cables ?

cause you half to have the key in the switch to start car when jump starting

CNB
 

·
Registered
2000 ML320
Joined
·
355 Posts
Yes that is exactly what that means. Jump starting with these vehicles should be avoided generally due to all of the sensitive electronics and (apparent) lack of surge suppression to protect them.

Same goes for changing the battery or connecting/disconnecting the battery for any other reason MAKE SURE THE KEY IS NOT IN THE IGNITION as the voltage surge can/will fry the key

If you have to jump start, make very sure that all of the electrical connections are tight before trying to start with the key
 

·
Registered
1998 ml-320 stock,oem bug deflector, nerf bars, leather gray upholstery, delivery date 25 nov 97
Joined
·
677 Posts
Discussion Starter #4
Magweed

thanks for the clarification

CNB
 

·
Registered
1990 190E 2.6,.... 1998 ML320, 2005 ML500SE
Joined
·
3,103 Posts
The RFID chip in the key never gets Fried as such. What happens is that the synchronization between the RFID chip and the DAS gets lost and there is no easy way to resync the key's RFID code to the DAS code.
What happens is that when changing battery, tying to start with a weak or dead battery or jumpstarting, one of the two (RFID chip or DAS) rolls to next random code without communicating new code to other circuit.
ie, you are SOL.
Mike
 

·
Registered
1998 ml-320 stock,oem bug deflector, nerf bars, leather gray upholstery, delivery date 25 nov 97
Joined
·
677 Posts
Discussion Starter #7
Thanks mike on explaining what happens to the chip.

Motohunter4

The flooding occurred in Roanoke Rapids I live in Weldon which is approx 1 mile away . Chockoyotte Creek passes under interstate 95 that is what overflowed and blocked interstate 95 ( that was approx 1 1/2 miles west from my home.)

Most of the flooding was in low lying arias next to Chockoyotte Creek. The Capstone paper mill was in approx 6 feet of water and it sits next to the Roanoke River. And the Halifax Regional Medical Hospital sit next to Chockoyotte Creek as well.

The rain started around 4 am and did not stop till around 8 am . We got approx 7-8 inches of rain in 4-5 hours in one morning !!


Thanks for asking about me :)

CNB
 

·
Outstanding Contributor
2002 ML320, 2003 A160, 2002 ML500, 2018 GLS350d
Joined
·
4,405 Posts
What happens is that when changing battery, tying to start with a weak or dead battery or jumpstarting, one of the two (RFID chip or DAS) rolls to next random code without communicating new code to other circuit.
ie, you are SOL.
Mike
I believe that the RFID immobilizer chip is fixed code - voltage surge can fry the DAS making it forget, while low voltage doesn't allow it to remember. In the latter situation, sufficient voltage will fix it. Otherwise the fried DAS needs to be replaced and the new one can learn the code of your old RFID chip.

In either case, your key is ok and can't be fried by jumpstarting. Unscrupulous dealers would happily sell you a new one.

It's the remote unlocking chip that uses rolling code.

P.S. What is SOL? We don't use that expression down under.
 

·
Registered
2000 ML430, 2000 E320 4matic Wagon, 2002 ML500, 2007 GL450
Joined
·
39 Posts
DrX,
I'm not sure what "SOL" means either.:wink_2: But, I think its kind of like " he is FUBAR'ed. "

Benz 4 jts
 

·
Registered
1998 ml-320 stock,oem bug deflector, nerf bars, leather gray upholstery, delivery date 25 nov 97
Joined
·
677 Posts
Discussion Starter #10
SOL = crap outof luck :D

I am not having any key problems I just read the posting and had a question about it

CNB



I believe that the RFID immobilizer chip is fixed code -voltage surge can fry the DAS making it forget, while low voltage doesn't allow it to remember. In the latter situation, sufficient voltage will fix it. Otherwise the fried DAS needs to be replaced and the new one can learn the code of your old RFID chip.

In either case, your key is ok and can't be fried by jumpstarting. Unscrupulous dealers would happily sell you a new one.

It's the remote unlocking chip that uses rolling code.

P.S. What is SOL? We don't use that expression down under.
 

·
Outstanding Contributor
2002 ML320, 2003 A160, 2002 ML500, 2018 GLS350d
Joined
·
4,405 Posts
I'm not sure what "SOL" means either.:wink_2: But, I think its kind of like " he is FUBAR'ed. "
We say "up s*** creek" (without a paddle). Or simply "screwed" which I think is an American term. :)
 

·
Registered
1990 190E 2.6,.... 1998 ML320, 2005 ML500SE
Joined
·
3,103 Posts
voltage surge can fry the DAS making it forget, while low voltage doesn't allow it to remember. In the latter situation, sufficient voltage will fix it. Otherwise the fried DAS needs to be replaced and the new one can learn the code of your old RFID chip.
If it is the DAS that gets fried than how come my other two keys still worked after a dead battery caused my first key to become inactive and how come a new RFID key was able to be programmed into the original DAS while the original key could not be used. This was under warranty so the dealer was simply not trying to sell me a new key if the old one could be recovered.

In either case, your key is ok and can't be fried by jumpstarting.
So you are confirming what I stated that the key does not get fried.
Mike
 

·
Outstanding Contributor
2002 ML320, 2003 A160, 2002 ML500, 2018 GLS350d
Joined
·
4,405 Posts
I believe that the RFID immobilizer chip is fixed code ...
On further reading, I retract that statement. Your explanation was correct, Mike. The difference is that the transponder chip can't advance its own code sequence in the way the remote unlock transmitter does. It has an EEPROM that gets written over each time its used. That's if this top-secret info is accurate (and I believe it is): rudeney explains about DAS

So you are confirming what I stated that the key does not get fried.
That's right, jumpstarting will never fry your key, IMHO.
 
1 - 13 of 13 Posts
Top