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2001 ML320
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Discussion Starter #1
Hi, all
I have 2001 ML320 which I really enjoy driving, got 170K running strong. However I just ran into strange issue as I was driving, car felt like the engine was going die as it suddenly lost speed, turns out the brake is acting up by itself, then I see exclamation mark flashing in dashboard and BAS/ETS light come up. It only happened once, then the light went out, so I kept driving, then it happened again. Then happened three times in a row yesterday so I had to pull aside and drove straight to local garage where I know.

Luckily I mainly drive local, (just can't imaging if I was on freeway)
I have been searching for this case but can't find a solid cause.
I've seen some MB report similar issue like this and saying dealer couldn't locate the problem and doesn't show up on code. They basically changed YAW rate sensor <- what is this? and that was it.

Wonder if anyone know the solution for this problem? I need my car.

thanks in advance.
 

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Super Moderator
99 ML430, 00 ML320, 05 E500 4matic Wagon
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You really should have the codes read. It is most likely a faulty sensor. Getting the codes
read will make it a lot easier to narrow down what is malfunctioning.
 

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Premium Member
02 ML320 06 ML500
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17,105 Posts
This problem is usually caused by a maladjusted or faulty/sticking Brake Light Switch. What occurs is that the Traction Control System believes you are driving with one foot on the brake and one on the gas pedal and returns the Throttle Actuator to the idle position.

Remove the cover below the instrument panel and then your present Brake Light Sw. and follow the instructions as if you were replacing a new one. Then check to see if the problem is corrected. Leave the cover off until the problem is resolved

If not buy a new Brake Light Sw. from the dealer and install. Then recheck.

Please UPDATE YOUR PROFILE in USER CP.
 

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2001 ML320
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Discussion Starter #4
Thank you for tye info. In fact, my buddy who works at MB dealer as technician in TEXAS (I wish he was here in CA) told me it could possibly be brake lamp switch which you mentioned. Took his advice and got a brand new one from the dealer ($35+tax) and replaced it myself. However it looks like I did not do any of the installation instruction manual you uploaded. :(

Hopefully that is why after replacing the switch, it still does it.
I will try to reload the switch following exactly how it says (pressing brake and releasing brake manually by hand, etc) and will repost.

I have been searching and this link Mercedes Benz Ml320 2000 - Service brakes - car safety information, failing parts, recalls, bulletins, complaints mentioned exact problem that I have. Those report says dealer could not find the problem or code but ended up replacing yaw rate sensor. (called dealer to find out the part is $600! Is this something I can get used?)
 

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2001 ML320
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Discussion Starter #5
Update

OK, I replaced the brake lamp switch. It seemed to work for about 4 days as I only drove local. One night I had to get on a freeway but I wasn't sure whether it was fixed or not so I stayed on far right lane (it was night after 8 o'clock). after driving about 12 miles, it happened while I am doing about 70mph!:mad:

Car is braking by itself, exclamation flashing, engine RPM is halting, thank GOD there was no one behind me. Got emergency light on, but could not move forward to get to the shoulder, as it is keep pumping brake. Finally I pulled over, sat about 5 min, with emergency light on, I got the car to exit off freeway, turned back home local and no more sudden braking. Now this really got me worried, so I took it to the dealer and they said they never heard of the problem but they found two code which was relay to ABS brake and YAW rate sensor. They said try replacing relay first as the relay is burnt and do YAW rate sensor later as it is expensive. I had them replace the relay and looked working until two days ago.

Then it happened again but this time, BAS, EPS light came on but engine was not affected. Looks like I need to change YAW rate sensor. :(
 

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Outstanding Contributor
2002 ML320, 2003 A160, 2002 ML500, 2018 GLS350d
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You can drive without fear of your ML braking itself by pressing the ESP off button. You have to switch it off every time you start the car.

Then you'll have more time to save up for the yaw rate sensor. Don't let it go forever.
 

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2001 ML320
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Discussion Starter #7
just saw the switch.

You can drive without fear of your ML braking itself by pressing the ESP off button. You have to switch it off every time you start the car.

Then you'll have more time to save up for the yaw rate sensor. Don't let it go forever.
In fact, I was looking down and there is was! ESP off switch. Didn't even realize there was a switch to turn that function off until I drove to local mechanic to replace YAW rate Sensor. :eek: I had this car for 11 years!

Hope this solves the problem.
 

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2005 CLK 500 at 92k miles
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Take it to a good indi and he might be able to fix the problem with used parts. I did not have the problem you are describing but my indi (euromotors in Pasadena, 30 miles from you) did an excellent job with a problem in the ECU module of my ML 430, replacing it with a different used one and saving me big $$.
 

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2002 ML320, 2003 A160, 2002 ML500, 2018 GLS350d
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43sqd, back in post #5 he had the codes read: "I took it to the dealer and they said they never heard of the problem but they found two codes which were relay to ABS brake and yaw rate sensor."

What is YAW rate sensor? What does that do?
todesto, you can type questions into the Google search box. If that's too hard to find, you can ask Siri.
 

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02 ML320 06 ML500
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43sqd, back in post #5 he had the codes read: "I took it to the dealer and they said they never heard of the problem but they found two codes which were relay to ABS brake and yaw rate sensor."


DrX, I am not interested in words or descriptions of what the OP says M/B told him. The code numbers are the important thing and this is what he must supply before any recommendations can or should be given.

If he doesn't have them then he must have the codes read again to justify replacing such an expensive part. But if you want to tell the OP to replace it based on what M/B told him (undocumented), then be my guest.
 

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2001 ML320
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Discussion Starter #14
Here are the codes:

This is what it says on the report.
Hooked up SDS, performed quick test. Had code C1401-016, C1000-057, C1120-004, 006, 009, 020. Inspected ESP relay. Found contacts burnt. Replaced Relay.

next page:
Light is not on right now. I do have codes. C1401 for high pressure/return pump, c1000 for control module and 4 codes burnt. Rec replacing the relay and letting customer drive vehicle.
 

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Timeship, see you yesterday, but you already knew that.
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Somebody spill their coffee?

I'd check and clean the connectors before I personally did a thing more.
 

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02 ML320 06 ML500
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This is what it says on the report.
Hooked up SDS, performed quick test. Had code C1401-016, C1000-057, C1120-004, 006, 009, 020. Inspected ESP relay. Found contacts burnt. Replaced Relay.

next page:
Light is not on right now. I do have codes. C1401 for high pressure/return pump, c1000 for control module and 4 codes burnt. Rec replacing the relay and letting customer drive vehicle.
These codes are far from being just a Yaw Rate Sensor and a relay. This is exactly why the codes must be posted.
 

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02 ML320 06 ML500
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What are these codes mean?
What they mean is you have an expensive problem on your hands.

Once code C1000 is set there is nothing you can test or repair. The ESP/ETS/Traction Control Module must be replaced. This is the first thing that must be replaced, and then all other codes could be a moot issue.

Code C1120 is for a faulty YAW Rate Sensor but do not replace it until the traction control module is replaced.

Code C1401 is for a faulty High Pressure Pump Motor to the High Pressure Unit. This is an easy repair by just replacing the brushes to the pump motor.


http://www.benzworld.org/forums/w163-m-class/1530501-c1401-abs-ets-bas-lights-come.html

Remove the Traction Control Module and copy the number down and then try to obtain a used one. After installing it, the codes must again be read. If C1000 appears that unit is useless and return it for another one. If C1000 does not appear then clear all other codes in the used module and drive the vehicle and see if any codes set. Then repair according to those codes.

Again, you must have the codes read and cleared in the used module before driving.

You then have three transmission codes which should be addressed after you replace the Traction Control Module.
 

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Discussion Starter #20
Thank you.

Thank you for your kind replies. I knew this is the place to ask when in question. :)
I took it to local Benz mechanic who had a good reputation and replaced YAW rate sensor by mechanic's recommendation after checking the car and code.

It has been three weeks and have not had a problem since.

After the replacement, ran the code and found nothing so I (hope) it fixed the problem.
 
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