Hi everyone, fairly new to this forum and this is my first post. Recently bought a 2008 ML350, with 70K miles. Over the last few weeks have had a situation occur that is concerning. I don't know what to search for, but am certainly willing to do my research, but am not sure what even to look for....so am hoping someone here can provide a little guidance. My only guess right now is something along the lines of the antilock brake system.

On all three occurrences, I start the vehicle, back out of parking, then when I go to accelerate, after I reach let's say around 5-7 mph, I hear a grinding noise, the vehicle loses acceleration immediately, and goes into a braking mode. I am on flat terrain, once was wet, today was dry. I am assuming the noise is my anti-lock system kicking in, but am not sure at all. I then let up on the accelerator, and come to a stop. The first two times, I put the car in park, then reverse, backed up a few feet, then engaged drive and the problem cleared. This last time, I was on a busy road, so had to engage my hazard lights and coast off the road into a parking lot. Again, I put the vehicle in reverse, then back to drive and it cleared again. On the dash, I get the symbol that is a yellow triangle with the "!" in it.

Additionally, I have heard another sound with each incident, that comes from what sounds like the area of the drivers side passenger door. It sounds like something loose in the door rolling or scraping forward and backward in the door congruent with acceleration and braking. Ie., when I accelerate, it sounds like it slides backward, when I brake, it sounds like it slides forward. Kind of like if i had left a screwdriver in the door after some maintenance. Not sure if it is related to this problem, but I am about to pull the door panel apart to see if there is anything in there.

Any hints on where to start looking or what system might be faulty? I appreciate any inputs you might have. Thanks for reading and entertaining my questions.
Brian

 

! in the triangle is traction control.


I would start with wheel speed sensors

 

SO after some reading and research, and taking the car out tonight, what I see is the ESP warning lamp as well as the ABS lamp come on. Flat terrain, slow speed. Does happen once the vehicle has warmed up, or least after it has rolled a few hundred feet.

I easily located the speed sensors, any ways for me to check to see which one(s) is bad? Or should I start with replacing fronts, then backs?
thanks

 

That I don't know.


Bet an MB service shop can read what is tripping the system.

 

Brought it to a local mechanic. Turned out to be a bad speed sensor...passenger rear in this case. Easy fix. thanks for the help.