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1998 ml-320 stock,oem bug deflector, nerf bars, leather gray upholstery, delivery date 25 nov 97
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Discussion Starter #1
I chatted with a bosh tec today and he informed me in order to test a crankshaft position sensor once it is out of the vehicle is to use an ohm meter .

The cps should measure between 600 ohms and 1000 ohms. Also to check to see if the cps is opening up due to heat attach ohm meter and use a hair drying gun set on medium setting and direct heat to the cps and after a few minutes see if the ohm reading across the sensor changes to open circuit.

CNB
 

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02 ML320 06 ML500
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I chatted with a bosh tec today and he informed me in order to test a crankshaft position sensor once it is out of the vehicle is to use an ohm meter .

The cps should measure between 600 ohms and 1000 ohms. Also to check to see if the cps is opening up due to heat attach ohm meter and use a hair drying gun set on medium setting and direct heat to the cps and after a few minutes see if the ohm reading across the sensor changes to open circuit.

CNB
What does this post refer to? Why are you posting this?
 

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1998 ML320
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Is it good info though? If it is a valid test of the ckps then it could eliminate a lot of needlessly replaced sensors. If i had one here ( that i wasn't using) i could put it on my scope and do a few other things. These are just going to be hall effect sensors. I doubt they are self conditioning as far as the signal so would be basic as this testing would suggest. Would be a good nugget of useful info if valid.
 

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

43sqd

it is to verify once you have the crankshaft position sensor out that it is indeed bad. This is what was told to me by a tech from bosh as to how they test the CPS to be sure it is indeed bad.

i though I would pass on to other members on here what the tech told me .

CNB



What does this post refer to? Why are you posting this?
 

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1998 ml-320 stock,oem bug deflector, nerf bars, leather gray upholstery, delivery date 25 nov 97
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677 Posts
Discussion Starter #5
re

DrX

according to what I have read from this forum sometimes a bad CPS does not throw a code. And I was not referring to someone to take out the cps and test it . But for someone who has already replaced the CPS with a new one and installed it . that way he could then check the old sensor to verify it was bad .

CNB


CPS are only needlessly replaced by people who try
todiagnose their cars with Google mechanic. Faulty CPS will throw a code when it makes your engine stall. Removing a CPS to test it with a meter is inadvisable. But hey, it's a free world. Do what you like.
 

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02 ML320 06 ML500
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DrX

according to what I have read from this forum sometimes a bad CPS does not throw a code. And I was not referring to someone to take out the cps and test it . But for someone who has already replaced the CPS with a new one and installed it . that way he could then check the old sensor to verify it was bad .

CNB
It's extremely hard to believe that a hair dryer could duplicate the heat of a 220 degree engine.
 

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Outstanding Contributor
2002 ML320, 2003 A160, 2002 ML500, 2018 GLS350d
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DrX

according to what I have read from this forum sometimes a bad CPS does not throw a code.
When my ECM cut power to my fuel injectors at 100 km/h, I trust that it logged the reason why. The techs read the codes, changed the sensor, and I was on my way.

We've given you enough clues, but you insist on barking up this CPS tree. Your truck hasn't started for over 7 days. You asked for advice, you've received it from the experts and from me. You're frustrated and we're frustrated. What's the point of seeking advice when you won't take it?
 

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1998 ML320
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613 Posts
Now I'm curious as to just how pulling out a sealed monolithic sensor can harm anything or would be any different than swapping in a new one. ?
 

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2000 ML430 (Sold)
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Wragie, you have the new CPS just sitting in your hand right now. Change the damn thing out bud ;)
 

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1998 ML320
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Yabut then my nice new shiny ckps would get dirty! :D

That and my #8 torx bog hammer hasn't shown up yet...
 

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1998 ml-320 stock,oem bug deflector, nerf bars, leather gray upholstery, delivery date 25 nov 97
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677 Posts
Discussion Starter #14
re

They didn't get to finish it,will be Tuesday when I get the news . I am hoping it is just the key an to be able to get a duplicate key made and not need a new one as I am on key 6 and 7. The AAM module on a 98 ml 320 is it under fuse box or under dashboard ?

I am trying to find out if a new AAM has been installed in the past , Car-fax and the VMI (vehicle master inquiry) indicate it has not been replaced. A few years back I managed to get a copy of the car-fax and the VMI from the Dealer.

I will post findings of the diagnostic as soon as I get them

Thanks !


Hey CNB, you said you would have results of your truck's diagnostic by Friday pm. Any news?
 

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1998 ml-320 stock,oem bug deflector, nerf bars, leather gray upholstery, delivery date 25 nov 97
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677 Posts
Discussion Starter #17
re

with that Information I am gonna shoot for obtaining a duplicate key of 6 and 7 instead of getting a new key # 8 depending on the diagnostic results on Tuesday

cnb

CNB, thanks for replying. You can stop wondering about the age of your AAM. If you're up to keys 6 & 7, you must be using the original AAM.
 

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2002 ML320, 2003 A160, 2002 ML500, 2018 GLS350d
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It's not possible to get a duplicate 6th or 7th key. If it was, they would have duplicated key 2 & 3. The chips are given unique serial numbers. To ensure security, lost/stolen keys are banned. The slots in the AAM can't be re-programmed to recognize a new key. Otherwise a thief with the right equipment could steal your car by hacking your DAS/AAM to authorize his key.
 

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1998 ml-320 stock,oem bug deflector, nerf bars, leather gray upholstery, delivery date 25 nov 97
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Discussion Starter #19
re

I was told by two dealerships that each key could be duplicated at least 1 possibly 2 times but only by the benz place where dealers have the keys made at
 

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2002 ML320, 2003 A160, 2002 ML500, 2018 GLS350d
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Perhaps you didn't read the lengthy link I posted in an earlier thread of yours, so here's the relevant excerpt:
KEY CONFIGURATIONS FOR DAS 2:

With DAS 2, there is a maximum of 8 unique keys per vehicle. These key IDs 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 IDs. 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; its 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.
 
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