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post #1 of (permalink) Old 05-29-2019, 11:56 AM Thread Starter
stalje
BenzWorld Junior Member
 
Date registered: May 2019
Vehicle: 99' ML430 - 99' ML320
Location: France
Posts: 12
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Quoted: 5 Post(s)
(Thread Starter)
Question Tricky ML430 limp mode (wrong front axle speed)

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 :
Tricky ML430 limp mode (wrong front axle speed)-img_20190516_190633.jpg

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 :
Tricky ML430 limp mode (wrong front axle speed)-img_20190529_194620.jpg
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 :
Tricky ML430 limp mode (wrong front axle speed)-img_20190529_194527.jpg
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!
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