immobilizer, Start Error

bhonok said:

The resistance of transponder coil is 3,2 not 5 ohms. Is it critical and can trigger "Start Error" ???

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According to the algorithm, if the coil resistance is under spec, you should replace it. Perhaps there's a short circuit in it that's causing the failure to read the code.

You'll know for sure when you replace it.

Thanks DrX. As I mentioned before I am quite far from everything and replacement will take time. Can't walk miles at 74...need something pronto. This coil is it car model specific or anything similar with 5 ohms will do? can I raise the resistance of this coil, like adding small resistor or it might affect it ability to read the key ? Is it easy to pry it apart, find short and snap back? Sorry so many questions...

Transponder ring and box immobilizer are connected with 2 grey wires. Can they be separated and mismatched

bhonok said:

Transponder ring and box immobilizer are connected with 2 grey wires. Can they be separated and mismatched

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How can they be mismatched if the truck was running fine at one time? Maybe I don't know what you mean.

Are there any junk yards in Panama?

I mean can I mismatch them if they will not be available as a whole unit from whatever source ?? Like in my case I have defect in coil... unless I don't understand and they must be a unit... There are junk yards in Panama, but ML is an extreme rarity.

bhonok said:

I mean can I mismatch them if they will not be available as a whole unit from whatever source ?? Like in my case I have defect in coil... unless I don't understand and they must be a unit... There are junk yards in Panama, but ML is an extreme rarity.

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From my experience, yes, if you can find a working Ring...but best to find the whole set. It's easy to remove as mentioned earlier and easy to get to, in case you need to show the junnkyard over the phone or email. The Ring acts as a signal pickup and the box act as an amplifier.

On a side note, let's make sure that your keysense is still working. Insert the key into ignition (without turning to any positions) and open the driver's door. You should hear beeping sound.

Thank CGL. No, there is no beeping sound when I open driver door with either keys in. There is beep with lights on... Also I just noticed a significant power drain as I turn key to second position. I did check my starter motor about 5 months ago... the reason was sometimes it wouldn't engage on turn of the key... at the time I didn't see connection and I don't recall seeing a message but everything is possible...

bhonok said:

Thank CGL. No, there is no beeping sound when I open driver door with either keys in. There is beep with lights on...

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With lights as in headlights or dash lights? I would assume you meant the headlights...and that's different.
Try different scenarios with the key inserted (without turning). Insert the key while driver's door is already opened. Sit inside with all doors closed and turn the key as if you were starting the vehicle then turn key back to first position and open driver's door again. The thinking behind this is to get the beeping sound when/while the driver's door is opened. If after different scenarios that you still don't get the beeping sound, then I'd suspect that your Keysense wire isn't being activated whenever you insert the key. The Keysense wire should be Orange on the Ignition Switch plug.
No keysense = no start! (will also display "start error").

CGL. I have tried all possible scenarios- no beep. Orange keysence wire in switch connected to 15c. I pulled the plug from switch and tried connecting 30 with 15 and then 15c to simulate turning of key. same message , no beep as I was opening door as I was manipulating... I guess key batteries only important for remote , so where do I go from here?

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I think CGL is onto something with the keysense wire. I can confirm that if the Keysense wire is not live the car WILL not start and display Start Error.

I would turn the key all the way to ignition. Turn it all the way back and leave it in there. and open the door. If it is not beeping then something is up with the Keysense wire.

Have you tried using a multimeter to see if the keysense wire is live when you the key is in the ignition?

Hi. I have measured voltage. All wires in ignition plug are alive all the time except green wire. I put positive to contact 30 and touched all others with negative they all showed voltage 12,7 irregardless of whether key in or out or if immobilizer 4 contact plug connected or not.... Thank you for link to Ebay. I have this item in my basket I just trying to figure out what is it that I need... Looks like my ignition switch plug has voltage all the time...

Gentlemen, I suspect that the beeping keysense feature is specific to US models, and the OP's ML270 isn't equipped with it. Mine doesn't have this either, or a burglar alarm or panic button.

DrX said:

Gentlemen, I suspect that the beeping keysense feature is specific to US models, and the OP's ML270 isn't equipped with it. Mine doesn't have this either, or a burglar alarm or panic button.

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good point!

haha guess mercedes must think everywhere else in the world that
A.) driver is smart enough not to forget about keys in the ignition
B.) you always remember where you parked your car
C.) there are not break ins lol

Gentlemen. Now with key-sense feature out of the picture I left with DAS ring with 3,2 ohms resistance rather than 5 as most probable culprit of Start Error message and I need a replacement . Is this right conclusion ???

bhonok said:

Gentlemen. Now with key-sense feature out of the picture I left with DAS ring with 3,2 ohms resistance rather than 5 as most probable culprit of Start Error message and I need a replacement . Is this right conclusion ???

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Have you verified power at (N26/4 pin 2)?

where are you measuring the 3.2 Ohms (give me diagram pins please)

sgtpepperaut said:

Have you verified power at (N26/4 pin 2)?

where are you measuring the 3.2 Ohms (give me diagram pins please)

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Hi. I measure resistance inside the ring between 2 grey wires possible ends of coil same wires that enter immobilized. Sorry can't give diagram...
about N 26/4 immobilizer,where exactly you want me to verify power ? pin 2 is 15C, pin 1 is ground , pin3 pink is read data , pin 4 blue vrite data... Probably at 4 wire plug that connects to immobilizer ????

Hi. as I measure voltages and resistance it becomes clear that my problem resulted by 2 components : Transponder coil with immobilizer or DAS module the one sitting inside EAM . Can somebody suggest simple test to eliminate one component or another.....
Thanks .
Boris