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2001 ML 320, Thule rack system, Hidden Hitch towing hitch
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Discussion Starter #1
My 2001 ML 320 is having the ESP/BAS light problem, accompanied by four episodes of the car locking up one of the wheels as though the ESP thinks we're going into a spin (even though we may be driving at 30 mph on a straightaway). I took the car into the dealer, and intially got a computer code indicating a problem with the ABS pump -- which I didn't believe, because that shouldn't make only one wheel lock up. After a week or so, when the problem recurred, I returned to the dealer; and this time the code indicated a bad yaw rate sensor -- which makes more sense to me: if the yaw rate sensor is feeding bad data to the computer, the car thinks it is going into a spin, and engages ESP.

The dealer wants over $1000 to fix the yaw rate sensor ($500 for the part plus labor). I want to DIY, since I read in this forum the part is plug-and-play.

Anyway, in reading old posts on this forum, it appears that the ML 320 has (at least) two kinds of sensors, a lateral acceleration sensor, and a yaw sensor. I have seen the part number 163-542-06-18 posted for the lateral acceleration sensor, but also part number 163-542-23-18 on a different post (an updated sensor?). But I haven't been able to find the part number for the yaw sensor.

Does anyone know what is the correct (and most current) part number for the yaw sensor? When I open up the center consol (I believe the yaw sensor is under the window control switches), will it be obvious which unit is the yaw sensor, and which one is the lateral accelerometer? And how, by the way, do you actually open up the center consol?

Thanks!
 

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'08 ML320 CDI
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884 Posts
I've been having the BAS/ESP light problem too (probably for more than 10k miles now). It does not affect the driving behavior of the car though. The light only comes on when when making slow turning maneuvers like parallell parking or making a U-turn. Once you're on the freeway orso, it turns off.

Any idea if this will affect the driving at some point? I have a feeling it's just some kind of sensor going bad making the light come on. Not sure though...
 

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2001 ML 320, Thule rack system, Hidden Hitch towing hitch
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Discussion Starter #4
The BAS/ESP light problem can go on for quite a while without any symptoms (e.g. the brakes engaging suddenly). In fact, if it weren't for the fact that I've actually had the ESP kick in out of the blue -- thus scaring the daylights out of my wife and me -- I would have just left the dashboard light alone.

My MB dealership told me "When the light goes on, it indicates the computer has detected a fault in the system. It doesn't necessarily mean the computer has shut down the ESP, or that BAS or ESP will not engage when needed." In other words, a faulty wheel speed sensor, ABS pump, relay, lateral acceleration sensor, yaw sensor, or brake switch (or any number of things) will make the light go on -- but ESP is not turned off unless you manually turn it off.

My guess is that, in my case, the light goes on when my intermittently faulty yaw sensor sends a bad signal to the ESP system. Unfortunately, sometimes the ESP thinks the bad signals are real signs of a spin, and the ESP engages. Of note, when I turn off the ESP (using the ESP OFF button on the dash), I don't get the dashboard ESP/BAS light, and I don't experience the sudden braking from ESP. I suppose that should make sense.

I'm still looking for that part number, though!
 

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2001 Mercedes Benz ML55 AMG
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36 Posts
I think I'm having the same problem, it just started. If I go into a sharp corner occasionally the ESP comes on. This started after I put too much air into one of the rear tires so I backed it down to the same preasure as the opposite one. It's really strange, I'm running a 2001 ML55.
 

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Outstanding Contributor
02 ML320 06 ML500
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17,274 Posts
did you replace this yourself? If so, do you have any references to DIY or pics?
The Yaw Rate Sensor is located near the shifter assembly and the center console must be removed. But you must be careful here, up to VIN #371934, there are two different sensors, a Yaw Rate Sensor and a Lateral Acceleration Sensor. As of VIN #371935 there is only one where they comprised both into one Yaw Rate/Lateral Accel. Sensor.

With that said, it is advisable to consider the fact that what worked for one, does not mean it will work for you. These are not cheap parts to buy, and after doing so and installing it, it might not remedy the situation. Most of these problems can be corrected by disconnecting the neg. battery cable.
 

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2001 Mercedes Benz ML55 AMG
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36 Posts
Instead of dropping a $1,000.00 I'm going to do the battery thing first. Thank-you very much for that suggestion, MAN... I luv this sight!!
 

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2001 Mercedes Benz ML55 AMG
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36 Posts
I unhooked the battery for about 2 hours and the issue with the ESP seems to be resolved... thank-you for the advice!!
 

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2001 Mercedes Benz ML55 AMG
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36 Posts
Hi....

Back with the same issue. When turning a corner the ESP will come on and off suddenly. Please keep in mind that this issue is under normal driving conditions, I'm not driving the thing like it's stolen.
 

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05 500
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6,550 Posts
Dting22, I have no solutions for you because my BAS/ESP/ABS.../XYZ lights haven't graduated to lock-up yet. Let us know what the solution is. it's a very scary problem. I know that last year another forum member had this problem and I don't recall whether or not it was eventually resolved. Please let us know as you make progress. There could be several solutions, like many ML problems are!!!!! Thanks.
 

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2001 Mercedes Benz ML55 AMG
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36 Posts
We'll do Darkmann. I need to get an outter tie rod done so I'm thinking of getting it diagnost then.
 

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Just to update this thread, I am a mechanic here in New York, I have a customers car which is a 2000 Ml320. They brought the truck to me cuz the brakes would ingauge for no reason. After scanning the car with my Launch X431 it cam up with c1120 (Rotary stored speed and lateral acceleration sensor): Signal cable has open circuit or short circuit. After a little research I replaced the yaw sensor (which is located in the center console under the window switches) and the problem was gone but with a little twist. It would not lock the brakes anymore but from time to time the bas light would come on.
After inspecting the vehicle I noticed a broken wire in the rear of the truck on the passenger side right above the axle. Now, I am not sure what this wire is for. The end of the wire has no connection (looks like it broke off) and there is nothing in the back that is missing a plug. There are three wires in the loom and it was constantly rubbing on the axle. I believe this is what was causing the BAS light to come on. Since tapping up the wires the light has not come back on. So for anyone having this problem I would sujest you make sure no wires are broken or touching anywhere.
 

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2000 ML55
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565 Posts
If the code tells you "Lateral Acceleration Sensor" what made you change the Yaw sensor?
 

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If the code tells you "Lateral Acceleration Sensor" what made you change the Yaw sensor?
This truck actually threw a lot of codes, but from experience I know a speed sensor would not cause the brakes to lock up. After further research on the way the BAS system works I concluded the yaw sensor was bad.
 

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2001 ML-320
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hey Dting!

Hey bod, I solved this issue a year ago, I don't know if you've had already and I don't have time right now to tell the whole story if you don't need to hear it. pls let me know if you haven't fixed it and I'll tell you what to do

take care
 

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05 ML500 SE
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1,482 Posts
Enrike - can you PM me what you did or post it here... I have been dealing with some annoying issues for a while that is either a wheel position sensor, lateral acceleration sensor, or yaw sensor.

Issue A. (more frequent)
I get the abs pumping the brakes when i am coming to a slow stop. Like as if the road is really slippery. Doesnt happen as often when coming to a hard stop mostly a gradual stop. This sometimes triggers all three dash lights to come on and stay on but not always... and i can clear them after a few ignition cycles.

Issue B. (less frequent)
I am crossing an intersection for eg.... the /!\ yellow triangle light will flash and i wont be able to accelerate for a few seconds. It doesnt seem to be when I am turning left but going straight. It feels like limp mode or the computer is cutting the throttle. It only lasts a few seconds but could be very dangerous. This happens several times per month and is worrisome. It doesnt always trigger the three warning lights to come on.


So I am wondering if I have more than one issue. One theory I have is the wheel position sensors are dirty or faulty and that is Issue A. And the lateral acceleration or yaw sensor is 'Issue B.' I just don't know and I havent had a chance to dig in to it yet.

Any ideas ladies and gents?

(PS - I have already changed the brake light switch)
 
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