Nathan S

Bought a used ML320 a year ago. Remotes didnt work, used car guy said the batteries were probably dead. They were not, there are other issues.

So after working on my ML320 keyless entry, I decided to pay the $200 to give the dealer a shot at it. They determined that my AAM is bad, they cant get a new one, and used ones are VIN-Locked so they have no way to fix it as an authorized repair facility. Also they mentioned errors between the AAM and EAM but would not dig into it.

Here's what I did before taking it to them:

1. The fobs are original, the interlock works fine.
2. Replaced the remote batteries.
3. Tried resync several times. On the last button press the dome light goes out but nothing after that. One remote did unlock the car exactly once.
4. Verified the remotes are sending (HAM radio spectrum analyzer sees nice power out of the fobs)
5. Replaced the AAM Antenna.
6. Replaced the AAM with a working junkyard unit with matching firmware/hardware version numbers and swapped over the MCU on the board (I am an EE with access to SMT gear). No change.
7. Looked into dumping the ROM and reprogramming a new MCU but XPROG-M programming gear is either bootleg or hundreds of Euros and no guarantee that the image is good anyway. Also I don't know if MB secures their flash.
8. The issue is likely the AAM/EAM communication but not sure how to attack that. Anyone have info on debugging a possible EAM/AAM communication issue?

So, to this forum, I ask, what are my options for aftermarket keyless entry? Can I get equivalent features, and can I get a plain non-switchblade key to replace my old ones? What are the odds that the dealer cannot add a new straight secure key to the interlock system? I don't want 2 fobs on my keychain.

N.

khomer2

Nathan,

some reading if you havent done so

Your physical oem blade on the FOB and valet keys) work - start up the suv with no issues, correct?
It's the FOB (remote locking/unlocking) that is no longer working, correct?

If this is the case, and you want a 3rd party wireless remote to lock and unlock (no alarm), then read here

Nathan S

Thanks for your suggestion, yes the blades and transponder chips are fine. The car came with two fobs and no valet key. The fobs looked like their dog had their way with them so I transferred the guts and blades to new plastics.

Looks like I will need to get a couple of valet keys made so I can ditch the switchblades. If they have transponders in them, great, I'll have the dealer add them to the immobilizer. If not, I can just make a nice little epoxy doodad to put on my keyring with the valet key. Maybe stick it to a nice leather fob from the dealer to rub their nose in it a bit 😁.

That is a nice thorough How-to, much appreciated. I can skip the bypass and remote start bits though..

I do want to get lock. unlock and parking light flash working with the system, I'm OK with a horn alarm output.

I also want to add automatic headlights so I might try to add that while I'm in dinking around with AAM outputs. I may have to Arduino something up for that. Why MB didn't have those in 2001 is a mystery. Cellphone in the car? Check. Auto headlights? Nicht für Sie, Scheißkopf!

N.

khomer2

The valet keys need to be ordered thru the stealership and yes, they already have the chip in the plastic part of the key handle. Provide vin# and proof of ownership.
As for automatic headlights coming on (aka DRLs), that has to be done with thru their Star system. I believe stealership has to change the programming in the AAM (All Activity Module) from USA setup to either EU or Canada.
The other option you have for DRLs w/o using your headlights (not sure what you have on yours - xenon or maybe halogen), but you can add led driving lights just below the bumper (if you dont have them) and tie them into your oem fog light switch on the dashboard. This would allow you to activate manually still and they would turn off, with ignition key turned off and removed.
====> read here

IgorE350

Hi same thing happened to me. Same exact problem you having. And noticed something very interesting. Did that happen to you after you changed your guts to new Chinese shell ?
Maybe i am crazy but i think them Chinese fob shells causing it. Right after i replaced my guts on my 03 ML350 after few days it stopped working, couldn't lock/unlock doors anymore, i couldn't even sync that fob back to the car again.
Lucky for me i had another OEM key and used it after that with no problems and didn't bother to replace the shell.
Then bought another shell to make my 01 ML55 kefob look good, only had one OEM fob for that car. Well my key for looked great but it stopped locking unlocking doors in few days and i am having same exact problem you having. When i try to sync the fob with the car i go through the steps and at the end when i press the button it unlocks the car ones and not working after that.
My guess is that when we changed to a new Shell somehow wile we driving the car one or 2 buttons get pushed on the fob at one time and stay pushed. I don't know if you noticed but them new shells buttons are very tight. Or maybe someone got other ideas what happened?
Hopefully someone will point us in the right direction how to fix this problem. Its kinda sux to have a nice Mercedes that you cant lock/unlock doors.
%70 of china goods are JUNK!

IgorE350

Any update on your problem?

jfrankha11

BIG QUESTION: SNCE THE DEALER SAID MY AAM is not communicating and they can not replace it (obsolete), can I replace all my computers with a used set from another car including the key, will that work since everything is synchronized/proprietary. No one in the Dallas area has any good news for me about the 2004 ML350 being able to be repaired. Does anyone have any suggestions, good interior, body, paint, new tires, good engine/tranny but I can't start it or go anywhere?