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Got a '98 ML320...AAM question

19K views 58 replies 7 participants last post by  Deplore 
#1 · (Edited)
Normally I troll the W210 forum -- but today I am the dubious owner of a 98 ML320. Classical symptoms of no start.

Symptoms: Cranks, no start.

PO: took vehicle to dealer. 2 key, new ECU, still same issue. PO was very vague when telling me about the problem, but when I diagnosed it, I believe it might be a bad AAM.

Code is B1703-003 -- The programmed code of the transponder is o.k., the programmable code is invalid.

When doing DAS module, AAM and key tests in the AAM module in HTTWIN, the immobilizer and AAM tests pass, but the key tests fail. I have three keys. All three fail the test.

The key remote also does not work, but the central lock works. Fresh batteries.



I've been trying to pin down exactly what module controls what. As I understand, MB changed the vehicle immobilizer (DAS) from the AAM to EAM in later years, or to the dedicated DAS module.

So my question is:

What does my 98 have? Is the hash key stored in the DAS module behind the cluster, or is it stored in the AAM?

I have a PnP nearby that has 3 ML's there, and I plan on going there to pull the radio (current car is missing a radio). While I'm there, I could also pull out the ignition key coil ring and AAM -- provided that they could be the culprit? What about the DAS module behind the cluster?

I just need a basis to start my search.

Thanks for any advice.
 
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#5 ·
No I didn't. The previous owner took the truck to dealer and that is what they told her it needed...so two keys and a ECU later, same issue.

It isn't a problem for me to reprogram a used AAM to the truck. Just a matter of finding the correct program that can sync the key rolling codes.

Can you be a little less vague? What exactly happened at the dealer? They ordered 2 new keys? Why would they, when one would be enough? Did the dealer get the engine started? Did the PO drive it home, or did the dealer give up and let him tow it?

If the new keys worked once, then you should replace the immobilizer coil and control module. Faulty ring or module kills keys by failing to write the variable code. When this happens, the AAM wants the next code, but the key still has the previous code.
This is the part where it gets murky. She said the battery went bad, truck wouldn't start. Replaced battery, same issue. Towed to dealer, dealer said it needs keys and ECU....No change. Dealer then said it needs something else, probably AAM (she still doesn't know which one it is, I need th get the service paperwork from her), and then she had the truck towed back to house. Then I bought it.

Interesting info on the key, sounds exactly like how BMW keys work. That's familiar territory. Hmmmm...

So possible faulty ring, possible faulty AAM? I'm going to wipe my AAM and program my original keys to it and see where that takes me.
 
#4 · (Edited)
PO: took vehicle to dealer. 2 key, new ECU, still same issue. PO was very vague when telling me about the problem, ...
Can you be a little less vague? What exactly happened at the dealer? They ordered 2 new keys? Why would they, when one would be enough? Did the dealer get the engine started? Did the PO drive it home, or did the dealer give up and let her tow it?

If the new keys worked once, then you should replace the immobilizer coil and control module. Faulty ring or module kills keys by failing to write the variable code. When this happens, the AAM wants the next code, but the key still has the previous code.
 
#14 ·
I have devised a method to resurrect a bad key transponder. Open up the dead key and remove the transponder pellet. Start the engine with the good key, and before moving off, tape the bad pellet to the side of the good key, as far inside the coil as you can. Orient it lengthways. Drive the car - when you hit 5 mph a new code will be written to both pellets.

Replace the bad pellet inside the key and try to start it. There are only 8 possible variable codes so if you're unsuccessful, you need to repeat this up to 6 more times.

Attempt this procedure at your own risk. I can't see how anything could go wrong, as long as you remove the pellet prior to the next engine start.
 
#15 ·
Well.

Got a good transponder coil from JY, put it in.

Now in AAM menu, AAM, immobilizer and key tests pass.

HOWEVER

AAM still doesn't recognize the key #, it's either blank or shows -?- when key number is. But it does recognize the terminal changes, etc.

I also took the AAM from the same truck, copied the info from the original AAM to the donor, but it wouldn't fit in the 98. I mean the AAM itself physically won't go in the fusebox. Pinout different?

I have a friend who has a MB key programmer, so I will appeal to him as a last resort.

And yes, I will try to revive old keys. Hate the thought of having 3 useless keys...
 
#17 ·
I know, but I do this for a living. I make MB keys for cars after 1998+ (electronic fobs, mind you), reprogram used ECU/TCM to MB, reprogram theft relevant parts to other cars, etc.

This is an affront to my professional skills....so I'm trying to do my best to fix it on my own, lol. :D

Dealer is the last resort, and if I can't do it myself, then I guess I'll tow it there. But last resort.
 
#20 ·
Continuing this from that other thread....

You can get the $37 key from an MB dealer. That would be too easy, though.
I may have to go that route, but at what point does the AAM recognises the keys?

I was able to get a brand new AAM, and the dealer parts guy says it does not need a programming key. So I stick it in my car, program it to the car, and it still does not see the key #. There is an option to make a new master key, but it won't work with any of my keys, including two new keys that I made myself. No change.

So I'm wondering, what is the exact relationship between the ECU, AAM and the transponder ring?

Is transponder ring coded to the car, or is it interchangeable?

If the AAM is replaced, does the ECU also needs to be replaced? How does the ECU validates the AAM?

I can easily reset the AAM and ECU back to factory blank slate, so if that is the route I should take, then I'll do it. But DAS2b makes no damn sense.
 
#22 ·
Aaaaah, that is excellent information. That was the missing link I was looking for. Thank you!

I pestered the parts guy, and he emailed me this. Page 4....

Interesting.

I will try to order the coding key and see if I can get it without needing to tow the car to the dealer.

Think my next step is to wipe both ECU and AAM back to factory, then use the coding key to proceed? Won't know until I try.
 

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#23 ·
For once, the age of the car worked in my favor. Dealer did not require the car presence, only my registration and driver license was needed.

$28 for a coding key...not bad. It'll arrive Tuesday.
 
#28 ·
I got the coding key, but it's black? I thought it was supposed to be green.

It looks exactly like my other key, which I believe it is a valet key.

But the part number is correct..... and it does not work. I cannot create a master key through the HTTwin menu as per that pdf. I think the transponder ring is bad, gonna order a new one tomorrow.
 

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#29 · (Edited)
But the part number is correct..... and it does not work. I cannot create a master key through the HTTwin menu as per that pdf.
You can't create the master key. You already have it. You use the master key to "learn transponders" in the AAM menu.

As the pdf says, once you have learned the transponder codes to the AAM, you can return the master key to its original state using the "create single-use master key" option.

If there is no "learn transponders" menu in HHTwin, then you have to use SDS.

As if I need to explain this to a key-programming expert (but it seems I do), "learn transponders" transfers the 8 codes in the master key into the AAM, then leaves the #1 code in the master key, so it can become the valet key and use track 1. "Create single-use master key" is the reverse of this process, putting the 8 codes from the AAM back onto the master key.
 
#30 ·
Well, whatever it is, it is not working. None of my old keys are being registered.

Also, I am using SDS. When I connect to the AAM, the SDS automatically calls up httwin.

The transponder ring fails the tests, so I have to order a new one anyway.
 
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