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WARNING!

OK, this is going to be long, so beware! Get yourself a good drink and curl up on the sofa and get ready to read. Hopefully, this will explain everything you ever wanted to know about the MBZ DAS system. I have gathered this information from various official MBZ sources, included technical documentation, service documents, and even authorized technicians and factory personnel. Because this is all “double-secret inside information�, I cannot guarantee that everything is 100% accurate, but I don’t believe I am terribly misinformed as does all seem to make sense.

ACRONYMS USED:

AAM (All-Activity Module) –the electronic circuitry that controls all vehicle functions except for engine and transmission systems.

ECM (Engine Control Module) –the electronic circuitry that controls all engine functions including ignition delivery and timing, fuel delivery, and fuel/air mixture.

DAS (Drive Authorization System) – the systems used by MBZ vehicles to validate a key for starting the engine. This is also the name of a specific electronic module either built-in to the AAM or attached to the AAM that performs the validation.

EIS (Electronic Ignition Switch) – the ignition switch on models that use the newer “bladeless� infrared key.

ESL (Electronic Steering Lock) – an electronic lock that disables the steering column on models that use the newer “bladeless� infrared key.

RCL (Remote Control Locking) –the function of the key fob that allows the vehicle to be remotely locked and unlocked.

CAN (Controller Area Network) –an electronic data bus that allows the different vehicle systems to communicate, i.e. the AAM and ECM exchange data over the CAN.

HHT (Hand Held Tester) – an electronic device used by service technicians to diagnose and program vehicle functions. It connects to the OBDII port and communicates over the CAN.

FDOK – MBZ worldwide database that contains all information about ever MBZ ever built, including the assignment of all electronic key codes for all vehicles using DAS.

PDC (Parts Distribution Center) – MBZ locations where parts are stored. Some of the PDC’s are authorized for the distribution of vehicle keys. Those that are have equipment capable of programming a specific fixed key ID from FDOK into a virgin key fob.

Now, on with the show…

THE DRIVE AUTHORIZATION FUCNTION:

All Mercedes-Benz vehicles manufactured in about the last ten years use DAS to electronically validate the vehicle’s key. Each key fob for this system contains an EEPROM chip that stores a fixed serial number and a rolling code. Each time the key is used in the ignition switch, DAS reads both the fixed serial number and the rolling code. These values are compared to known valid values stored in DAS. If a match is found, the ECM will allow the engine to start and run, and DAS will write a new “randomized� rolling code to the key fob’s EEPROM. If the key fails validation, even if it is mechanically able to turn the ignition switch, the ECM will prevent the engine form running.

Every Mercedes-Benz vehicle has a record in FDOK. When the record is created for a new vehicle, a set of unique key serial numbers is assigned and stored in FDOK. Only certain authorized employees at authorized PDC’s have access to this information. Authorized PDC’s stock virgin key transponders and have special equipment to program them with valid serial numbers from FDOK. Keys are programmed when key set is ordered for a new vehicle or an additional or replacement key is ordered for an existing vehicle. Only a factory or an authorized service center can order keys. For existing vehicles, the service center is required to verify that the customer ordering a key is in fact the owner of the vehicle in question. Examining the customer’s photo ID and the vehicle’s registration receipt generally satisfies this.

For new factory vehicles, there is an operation that performs the initial programming of DAS to introduce it to its assigned key set. This loads all the pre-defined key serial numbers into DAS as defined in FDOK. Even though not all keys physically exist, all possible key ID’s for that vehicle are loaded. This is performed in different ways depending on which version of DAS the vehicle uses. Once performed, there is a “marriage� process that irreversibly locks this data into DAS. Once married to a key set, DAS will only recognize keys in that set. Officially, there is no way to reverse this process and introduce a new key set to DAS, nor is there a way to alter any of the individual key ID’s know to DAS.

DIFFERENCES IN VERSION OF DAS:

There are two versions of DAS – version 2 and 3. Version 2 generally uses the rectangular fob and a mechanical “switchblade� to operate the ignition switch. This is the style key used on all W163 M-Class vehicles. Version 3 almost exclusively uses a tapered fob key with an infrared interface and has no metal blade for the ignition switch. The exception is that MY2002+ W163’s use DAS 3, even though they retain the rectangular fob and metal blade ignition key.

The main difference between DAS 2 and DAS 3 is in the way the key is validated. With DAS 2, the key is validated only by the DAS/AAM module, which in turn sends an “OK to Start� signal to the ECM via the CAN. With DAS 3, the key’s ID is actually transmitted over the CAN where the ECM validates it. For the W163 using DAS 3, the key’s ID is read by the DAS/AAM module and transmitted over the CAN. For other models with DAS 3 that use the infrared interface, the EIS reads and transmits the ID as there is no dedicated DAS “module� in these vehicles, although the “system� is still referred to as DAS. There was also an original DAS version “1� that did not use a two-way communication rolling code system.

For all versions of DAS, there is no battery required for the key. The battery in the key fob is used only to power the RCL functions. The power for the DAS functions comes from an electronic coil mounted in the ignition switch housing that supplies inductive current to the circuitry in the key fob. For DAS 2 vehicles (and W163’s with DAS 3), this coil is also used to transmit and receive radio frequency signals for reading and writing the key’s EEPROM. For DAS 3 vehicles (except the W163), the transfer of data between the EIS and the fob’s EEPROM is performed via an infrared signal. Also, since there is no mechanical blade to unlock the ignition switch, the release of both the ignition switch and the steering column lock is performed electronically once DAS validate the key through the infrared data exchange.

KEY CONFIGURATIONS FOR DAS 2:

With DAS 2, there is a maximum of 8 unique keys per vehicle. These key ID’s are programmed into a virgin DAS/AAM module at the factory using the valet key, also known as the “One-Way Master�. This master key is programmed at the PDC with all eight pre-defined key numbers as assigned to the vehicle in FDOK. At the factory, the master is used along with the HHT to initiate the download of these ID’s. Once the download has taken place, the key set can be married to DAS either by a function on the HHT or after 50 engine starts. The one-way master then becomes one of the valid 8 key numbers and is designated as the valet key. Other than lacking the RCL functions, the valet key has the same EEPROM and programmable rolling code functions as the rectangular fob keys.

When a new key is requested, either because one is lost or the customer desires an additional spare key, it is ordered from the PDC where it is created with the next unused key number according to FDOK. If the key is a replacement for a lost key, the service center technician will disable the key number of the missing key. This can be done as either a reversible or irreversible process. This has no effect on the RCL function; it’s programming is handled separately within the AAM. This means that it is possible to have a key that can function for RCL, but not start the engine. Once all eight key numbers have been created by the PDC, any additional keys would require replacement of the DAS module and the creation of an entirely new key set from the PDC.

KEY CONFIGURATIONS FOR DAS 3:

With DAS 3, there is a maximum of 24 keys per vehicle, however only 8 can be active at a time. Basically, DAS 3 has the same 8 key numbers as DAS 2, but for each key number, there are three key “segments�. The valid key numbers and segments are programmed into the virgin ESL, EIS and ECM using a special green-colored “workshop key�. As delivered, the vehicle will have two keys using key number 1, segment 1 and key number 2, segment 1 (some models were delivered with three keys, the third one using key number 3, segment number 1). When a new key is ordered, the PDC determines which key number and segment to supply based on whether the key is a replacement for a lost one or and additional spare key.

If an additional spare key is requested, then the PDC will create it as the next unused key number, segment 1. If a replacement key is requested, the technician must determine which key number was lost and order its replacement. The PDC will create the replacement with the next unused segment number for that same key number. When the replacement key is first used in the vehicle, DAS will disable the use of the key using the same key number and the previous segment. For example, if key number 2 is lost, the technician orders a replacement for key number 2 and the PDC supplies key number 2, segment 2. When this new key is used in the vehicle, this will disable key number 2, segment 1. Even if that lost key is found, it will no longer operate the vehicle. If key number 2 is lost again, the technician again orders a replacement for key number 2 and the PDC supplies key number 2, segment 3, which disables key number 2, segment number 2. If key number 2 is lost again, the PDC will supply a key with the next unused key number, segment 1, and the technician will be instructed to disable key number 2 completely using the HHT. Note that RCL functions are tied to DAS 3 so no additional programming is necessary to disable a lost key from RCL.

A FEW NOTES:

With DAS 3, virgin components (ESL, EIS and ECM) are shipped with Transport Protection. This allows these devices to function only in a limited test mode until they are authorized using the green workshop key. This would prevent stolen virgin components being used to bypass the DAS security on an existing vehicle.

For the W163 M-Class, the DAS circuitry was integrated into the AAM circuitry for model years 1998 and 1999. Beginning with model year 2000, the DAS circuitry was placed in a separate module that is externally connected to the AAM. This allows for an easier and less expensive replacement of DAS in those vehicles.

As of model year 2002, the W163 M-Class was built using DAS version 3. However, because the older style fob and mechanical key was retained, the system still only allows for eight key numbers with no segment designations. The eight valid key numbers are stored in the ECM and these values are not “field programmable�. The ECM and key set must be ordered together, pre-programmed at the PDC.

It is theoretically possible that with the PDC could create a W163 key that is a “clone� of the serial number of an existing key with the correct mechanical blade. Because the key would not contain the same rolling code as previously assigned by the vehicle’s DAS, it would not be recognized as valid.

There is a way that an in-service DAS version 2 module can be reprogrammed to change the eight key numbers that it recognizes and also to indicate that any or all of those key numbers are “virgin� keys so that they do not have to have a valid rolling code. This would be how to use a “foreign� key from another vehicle. MB corporate prohibits any authorized service from doing this. Furthermore, there is conflicting information about how this is actually performed. Some data suggests that it can be performed using a certain version of the HHT. Other data suggests that it required removal of the EEPROM form the DAS/AAM and having it “manually� programmed using appropriate electronic equipment.

Since DAS version 2 does not have the ECM validate the key (it relies on that validation being performed by the DAS/AAM), it is theoretically possible to simulate the validation over the CAN bus and bypass DAS security. This would require the appropriate equipment to interface with CAN signaling as well as knowledge of the CAN’s protocols and functions.

IN CLOSING

Well, that is all I know about DAS. I hope this information is helpful and that you are still awake!
 

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WOW!![:0]
 

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Thanks for that very clearly written and informative piece.

I assume this is partly your answer to this thread.

http://www.benzworld.org/forums/forums/thread-view.asp?tid=1244728&posts=14&fid=29


Basically, it's theoretically possible to clone a key after all 8 have been used up but it's not easy and depends on the skills and willingness of your local MB dealer.
 

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Discussion Starter #5
bigcatny - 1/20/2006 3:01 PM

Thanks for that very clearly written and informative piece.

I assume this is partly your answer to this thread.

http://www.benzworld.org/forums/forums/thread-view.asp?tid=1244728&posts=14&fid=29
Yes, I was writing the answer and just decided to go ahead an make a thread with everything I knew.

Basically, it's theoretically possible to clone a key after all 8 have been used up but it's not easy and depends on the skills and willingness of your local MB dealer.
It’s not just theoretically possible to close a key, it can be done. The problem is that it can only be done with the equipment at the PDC, and I can guarantee that no one with the authority to use it would do it.

The only other alternative is to re-program DAS to accept a key that was not part of the original key set assigned by the PDC in FDOCK. That is what I a m a bit sketchy on how it can be done, but I do know it has been done, or at least I was told by a technician I trust that he has seen it done.

One other thing I forgot to mention is I do not believe a technician can tell just by looking at the vehicle if all eight keys have been assigned. The only way to know for certain is to contact the PDC and have them lookup in FDOK which keys have been created.
 

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Wow, an opus magnum. Great!


PS. I suspect quite a few MB dealer mechanics are not aware 2002+ W163s are FBS3!
 

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How many keys can be issued for a 2004 ML500?

Rudeney, I re-read your post more carefully and in it you state that even in W163 vehicles using DAS3, there is an 8 key limit. I had heard elsewhere that there is a 24 key limit for MY200+. Even my dealer seems to be confused on this, as the service dispatcher thinks there's an 8 key limit on ALL MLs, whereas the parts desk guy said that for at least 2003+ models, there's and I quote "bunches of keys that you can order for 'em" unlike for my '99. Can you clarify this ? I may also contact MBUSA with this question. I'd like to get a new ML but if there's still a limit of 8 keys they can forget it unless I can find out how many have already been issued on a particular VIN.
 

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keys

Definitely check, parts department can request information on keys remaining.
Don't get stuck like me and charged $3600 for new key and locks.
 

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ljcml said:
... I'd like to get a new ML but if there's still a limit of 8 keys they can forget it unless I can find out how many have already been issued on a particular VIN.
I sincerely hope that this will not be the primary reason you'd not by a new ML. By new, I assume you mean the W164 (BTW, the # of allowable keys for that may be different than for the 163!!!). Even if you plan to get a used 163, you'll get a set of keys and all you need is a single key to drive the car. Do you plan to loose your keys in a short period???

Thanks rudeney for the post. Quite infoprmative. Do the 04+ have DAS3? I'll talk with my SA when I get home next week. I don't plan to loose my keys but it'd be nice to know.
 

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OK, lets replace the electronics... But why can't MB pdc give you a new black box, but let you use the old mechanical key blanks so you do not have to re-key the ignition, doors and tailgate. They are perfectly good parts being replaced for??? I can accept ridiculous, but they are going way beyond. Why don't they make us all dance a jig too. If they are the best engineers (and I think Porsche has them..) figure it out that they will have to work at Porsche if the lose their customers to stupidity. Come on, MB does still make some of the best cars, but don't include the stupid with it.
Lee
 

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Hi there!

The RCL (Remote Control Locking) "the function of the key fob that allows the vehicle to be remotely locked and unlocked" is not working on my 2001 ML 320.
Is there a way to reset it or fix it with out replacing the AAM II module? (keys are ok, with new batteries, resynchronizing have been tried a million times but nothing happen)
When the problem first happened, a couple of months ago, I took the truck to my local Authorized Dealer and they quote $3,600 to replace the AAM and the ECM.
Since the truck is running ok with out the RCL I have kept looking for options to solve the problem.

Thanks in advance.
 

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Hi there!

The RCL (Remote Control Locking) "the function of the key fob that allows the vehicle to be remotely locked and unlocked" is not working on my 2001 ML 320.
Is there a way to reset it or fix it with out replacing the AAM II module? (keys are ok, with new batteries, resynchronizing have been tried a million times but nothing happen)
When the problem first happened, a couple of months ago, I took the truck to my local Authorized Dealer and they quote $3,600 to replace the AAM and the ECM.
Since the truck is running ok with out the RCL I have kept looking for options to solve the problem.

Thanks in advance.
You should have asked your question by reviving your original posts on this subject. That way everyone would know what was suggested and therefore prevent repeat suggestions.

I suggested then that you remove the AAM from the fuse box and check to see if the antenna was damaged or possibly not attached, but you never replied.

Then you said that you were getting a new AAM or wanted to, but you never updated on anything.
 

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Sorry for the lack of information update.

I did removed the AAM from the fuse box and check to see if the antenna was damaged or possibly not attached, there is thin black a cable firmly attached to the AAM module on its side.

Thanks.
 

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fuel cutoff

One question I have about the DAS system is how it disables the fuel. I have read that sometimes the starter will still be enabled but there will be no fuel supply. I believe this is happening to my car purchased it from a small car dealership as a project car not MB. The car gets fuel to the fuel rail and I believe that the pressure is good, but I am only getting about 6 volts to the injectors therefore no fuel. I believe that the DAS is not providing authorization. Can anyone confirm this?
 

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One question I have about the DAS system is how it disables the fuel. I have read that sometimes the starter will still be enabled but there will be no fuel supply. I believe this is happening to my car purchased it from a small car dealership as a project car not MB. The car gets fuel to the fuel rail and I believe that the pressure is good, but I am only getting about 6 volts to the injectors therefore no fuel. I believe that the DAS is not providing authorization. Can anyone confirm this?
You are on the wrong forum asking this question, but after looking at the powertrain management wiring diagrams for your car I can say that is is extremely more complicated than the ML diagram.

With that said, whether or not you are having a DAS problem, I can only tell you with certainty, that injectors are powered up once the key is turned to the on position. Then once the key is turned to the start position the eng. computer sends a grounding signal to the injectors, allowing fuel to the cylinder.

If you had a DAS problem, the injectors would not receive a ground signal from the computer...............it would not reduce or eliminate voltage to the injectors. Check the appropriate fuse labeled for the fuel injectors and take a voltage reading on both sides of the fuse. If it shows 12v then the wires to the injectors should show 12v. If it doesn't show 12v, then there is a wiring problem to that circuit/fuse.
 

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Hi there!

The RCL (Remote Control Locking) "the function of the key fob that allows the vehicle to be remotely locked and unlocked" is not working on my 2001 ML 320.
Thanks in advance.
Hi all!
sorry for my english:)
i have same problem with key, sometime work, but no always:confused:
my first problem:
when i press lock - my ML350 2003 only switch in alarm system but no lock doors, sometime may be it lock doors. when i press unlock - its work only with driver door, double press for unlock other doors sometime work sometime no.
and second problem - main door central locker not work propertly - sometime lock and unlock.:mad:
may be anybody help me:bowdown:
Thanks in advance!
 

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Hi all!
sorry for my english:)
i have same problem with key, sometime work, but no always:confused:
my first problem:
when i press lock - my ML350 2003 only switch in alarm system but no lock doors, sometime may be it lock doors. when i press unlock - its work only with driver door, double press for unlock other doors sometime work sometime no.
and second problem - main door central locker not work propertly - sometime lock and unlock.:mad:
may be anybody help me:bowdown:
Thanks in advance!
In the pdf below, on page #33 you will find how to activate the Central Locking feature (highlighted in green) and then on page #293 you will find how to re-synchronize the remote. Other than that, you will have to seek the assistance of the dealer since it is a very complicated system.
 

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In the pdf below, on page #33 you will find how to activate the Central Locking feature (highlighted in green)
its dont want to work, i tried , its haemorrhoid with central switch,
i not need for automatic locking, i need simple lock/unlock passenger doors!!!
and then on page #293 you will find how to re-synchronize the remote.
re-synchronize many time, key is work for security system but not work for lock/unlock all doors

can be a key not guilty in problem?

thanks!
 
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