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-   -   Tricky ML430 limp mode (wrong front axle speed) (https://www.benzworld.org/forums/w163-m-class/3027630-tricky-ml430-limp-mode-wrong-front.html)

stalje 05-29-2019 11:56 AM

Tricky ML430 limp mode (wrong front axle speed)
 
3 Attachment(s)
Hello everyone,
I'm sorry to open yet another thread about some kind of ABS/BAS TCS etc... issue.
But this one may be different, since I was not able to find any other that was similar.

Let's begin with the context :
I bought this ML already in limp mode. The owner had bought an ML55 AMG and was not interested anymore in fixing this ML430.

Symptoms :
When I turn on ignition, I hear several beeps coming from the binnacle. Then I start the engine and here are the lights that remains illuminated :
https://www.benzworld.org/forums/att...516708&thumb=1

In this situation, the gearbox is stuck in 2nd gear. The engine itselft work as it should. I'm able to reach 75km/h then the car slow down itself to keep under this speed (ignition shut I guess).
Of course, I'm unable to use sequential gear selection and the low range can't be engaged.The speedometer remains accurate.

I borowed a Delphi diagnosis tool and was able to find interesting data :

Engine section is showing a p1605 fault :
https://www.benzworld.org/forums/att...516710&thumb=1
I saw another description of this fault mentionning incoherent wheel speeds (that's important)
Before, I also had a fault about gearbox selector miscomunicating but I replaced the conductor plate and the plug, and I don't show up anymore.

If I go the the data list of the engine section, I can reach #49 and this is the front axle speed : this one remains at zero whatever the real speed is. #50 is about the rear axle speed and this one is accurate.

That was for the engine section.

Now, if I go to Instruments section, I have no faults stored, but additionnal information about each wheel speed :
https://www.benzworld.org/forums/att...516712&thumb=1
So, that's explaining why I obtained the speed I mentionned before : the front wheels sensors are always reading this value : 32768 Rpm
The rear speed sensors are accurate.

Both speed sensors are new and I tested wire continuity from the plugs to the ESP module : everything is in order.
I have to mention I also have a ML320 that is working perfectly. I took its ESP module and installed in the 430 : same phenomenon.
I also replaced the ABS motor controller and no change. I tested the ABS motor itself by shortwiring the replay and it works perfecly.

The only way to display 0 RPM the the front wheels is to unplug the ESP module...

So... here I am. In a CUL DE SAC.

I would be really thankful if you could try helping me sorting this out... I have no idea what to do now.
Btw, sorry for the potential horrendous mistake I can make while writing... I'm not too familiar when english.

Cheers!

DrX 05-29-2019 02:30 PM

I think you need to buy/borrow a pro level scanner that can read and clear codes in the ETC module. The popular model on this forum is the Autel MD802 All Systems.

Then post the 3-digit code/s from the ETC module.

stalje 05-29-2019 11:51 PM

Quote:

Originally Posted by DrX (Post 17800200)
I think you need to buy/borrow a pro level scanner that can read and clear codes in the ETC module. The popular model on this forum is the Autel MD802 All Systems.

Then post the 3-digit code/s from the ETC module.

isn't that just what I already have ?
Do you think that the device you mention can really go further ?

Witek_M 05-30-2019 05:23 AM

Quote:

Originally Posted by stalje (Post 17800628)
isn't that just what I already have ?
Do you think that the device you mention can really go further ?

Have you tried connecting that scan tool to your working ML320 to see what speed values are displayed?

Why is SRS light on?

stalje 05-30-2019 06:30 AM

Quote:

Originally Posted by Witek_M (Post 17800734)
Have you tried connecting that scan tool to your working ML320 to see what speed values are displayed?

Why is SRS light on?

Yes, on the ML all the info are coherent. 0 rpm and 0km/h when idling and increasing when rolling.
The SRS light is on for another fault that I have deleted since that.

stalje 05-30-2019 06:32 AM

Quote:

Originally Posted by stalje (Post 17800778)
Yes, on the ML all the info are coherent. 0 rpm and 0km/h when idling and increasing when rolling.
The SRS light is on for another fault that I have deleted since that.

ml320*

DrX 05-31-2019 03:14 AM

Quote:

Originally Posted by stalje (Post 17800628)
isn't that just what I already have ?

I donít think so. If it was, you would have the 3-digit ETC codes, and have escaped limp mode.
Quote:

Do you think that the device you mention can really go further ?
Yes. Clear the codes in the ETC and ECM, drive the car out of limp mode, and if/when it goes back, read the codes from both modules and the ESP/BAS control module and post them here.

stalje 06-04-2019 08:58 AM

Quote:

Originally Posted by DrX (Post 17801528)
I donít think so. If it was, you would have the 3-digit ETC codes, and have escaped limp mode.

Yes. Clear the codes in the ETC and ECM, drive the car out of limp mode, and if/when it goes back, read the codes from both modules and the ESP/BAS control module and post them here.

Thanks for the advice, I'll think about buying this tool, so.

stalje 06-15-2019 02:29 AM

I bought the diag tool you adviced me. And it seems to be quite complete thank you.

Here are the specific codes that I read from the ml430 !

C1100 : Unkown
C1101 : Unkown
C1140 : Unkown

C1025-008 : Fault in CAN communication with control unit N47-7 (ABS control module). If no customer complaint exists, the fault can be erased

They are all the fault that come back immediatly after an erase.
Hope they (and you : ) ) will help finding me where is the issue on the car...

DrX 06-15-2019 02:53 AM

Youíre welcome.

Did you get it out of limp mode?


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