guanabara

MY friend has a 2000 ML320 and he experienced this problem twice. He took it to a regular mechanic who experienced the same issue (dangerous may I say) . He doesn;t know what the mechanic replaced but after that the problem went away. I would not call this a random problem when 2 or more are seeing it. It may be one of those buggy software behaviors when sensors/switches don't behave perfectly as expected when new as it happens in real life. This seems a good example of letting too many kids or people without relevant experience write software for complex machines such as cars.). Why would it be safe to apply brakes on all 4 wheels for whatever sensor failure issue?). The only plausible software programming I could see though would be for the assisted braking if the brake pedal switch were to fail and somehow tell the computer system that the driver must have pressed the brake pedal too fast possibly to avoid an accident or hit something. So just for the fact that the brake pedal position switch is cheap enough and easy to replace I would get that taken care of first. If the car is doing 55MPH and then suddenly the brakes are applied hard I am sure lots of lights will come on the dash as sensors will indicate wheel lockup and even traction issues, so I believe that the lights that came on were more the results of the reaction to the switch failure, which was to "assist" the brake response by applying full braking autonomously. Now if this is a generic design issue with the brake pedal switch due to quality control or lack or redundancy verification it would be a totally different question with regards to quality/safety controls. Funny enough this would a kind of issue that may not even be logged as applying brakes hard by hitting the brake pedal fast is possibly something that is not recorded. I would think that anything that triggers the car to autonomously take an action should be logged, even if most of the time it is not due to a part fault.

Dr Pain

https://www.youtube.com/watch?v=qgwb...ature=youtu.be

My right front brake just caught on fire after a 40 mile drive. I had new brakes (rotors and pads) put in by a Mercedes specialist less than 200 miles ago. I called them up and they think it is the yaw rate sensor. The car did not pull or make any sort of noise and no warning lights came on. I will update as I find more.

Maj. Dundee

When this happens it is usually the brake caliper that freezes up.

fordsbetter

I just got a 2000 ml320 called the company to get the code for radio they said theres a recall on the brakes any mercedes dealer will fix

my gauges stopped working after the ignition got stuck took out the tumbler filled down and the pins. does anyone know how to get the gauges to work.

art_arev

Open a new thread. This is not a bazaar.

Welcome to the forum

jcrebs

Have an ml320, 2002, bought new, 213,000 miles. Car has braked on its own several times, Bas/Esp light comes on when this happens. Took it to a local shop, they ran the codes and replaced the brake light switch, however this did not fix the problem. Spoke to the mechanic, asked if hitting the ESP dash button at every start up would turn off this system, and prevent this from happening, he said yes. Unfortunately , even with the ESP turned off, and the triangle warning light on, while slowing down and braking a couple of times, the brakes assisted by applying hard and pulling hard, and then the Bas/Esp light came on, and the triangle warning disappeared. Have also noted that several times when driving, and not applying brakes, the triangle warning went off, and the Bas/Esp light came on .The car has never braked on its on when the Bas/Esp light was on, only when the triangle warning light was on, or when no light at all was on. Have read all the comments in this thread, and similar comments on other sites, and it seems that even MB dealers cannot always solve this problem . The yaw rate sensor seems to be the likely culprit, but I am hoping to be sure before I have this replaced. Does anyone know why hitting the ESP button, and supposedly turning the system off, why this could still happen, and also is there a way to permanently disable this system, so that the car can't ever self brake again?

Maj. Dundee

Yes it is probably the Yaw Rate Sensor, but to make sure you will need a scanner that can read ABS code, namely C1120 Yaw Rate Sensor or C1142 Lateral Acceleration Sensor.

jcrebs

Thanks for the codes. If it is determined that the Yaw Rate Sensor is the cause of the self braking, can the Yaw Rate sensor be removed, not replaced, to stop this problem?

Maj. Dundee

Absolutely not. It must be replaced or nothing will work.

jcrebs

codes were c1120( 5120) status: current
c1120 ESP Yaw Rate Sensor ( b45) ; signal cable open circuit/ short circuit, is the print out that I received.
Price to replace part $ 980, w/o a guarantee that it will fix the problem, so am mulling over my options.
Questions: 1) With the ESP button pushed off, why will it still self brake?
2) With the ESP button pushed off, after about 10 minutes of driving, the warning triangle stops, and The ESP/BAS simultaneously lights up. It has not self braked with the BAS/ESP light illuminated, does anyone understand the reasons for the self braking with the ESP button pushed, but not when the ESP/BAS light is on?

Maj. Dundee

Resolve yourself to the fact that you have to replace the Yaw Rate Sensor and after replacing it the code/s must be cleared.

DrX

Your other option is to salvage a working used module from one of the growing collection of retired MLs in junkyards.

If you need a guarantee, you can have a dealer fit a new sensor. If that doesn't fix it, they can put your old one back in and you don't have to pay for the new one they tried.

The car doesn't brake by itself if ESP is switched off, but I suppose the Brake Assist System is still operable.

jcrebs

Could not find a used sensor in my area, had a new one installed, driven 50 miles w/o problem , hoping that this solves it.
Re Having ESP switched off, when I hit the brakes , sometimes it would "assist" rapidly, so the brake assist was still "working" in these cases, but it did not brake on its on with ESP switched off.

n3o23

I have a 2002 ml320 that when I am stopped and turn left the break grinds ( sounds like ABS) but it only does it at 2 to 7 mph. It only happens on the left front wheel and only turning left. I get ABS lights every once in a blue moon when it drags hard. If I press the ESP Off button it makes no difference whats so ever. Do you guys think this is the same issue or a different issue all together.


Thanks in advance.

Maj. Dundee

That's not an ABS issue. Have you taken the L/F wheel off to investigate?

n3o23

I have removed the wheel and inspected the calipers, brakes, cv joints and don't see anything out of the norm

Maj. Dundee

You must make sure that the backing plate is not rubbing up against the lower rear of the rotor.

n3o23

Ok I will check this tonight after work. But it feels like the brake is beefing applied on it. Sometimes the car has problems getting going turning left like the break is applied.

Thanks again

n3o23

Sorry just now getting back after tearing more into it. There is no rubbing anywhere on anything. So yesterday I swapped out the caliper and the brake line with same results. The other night going through a drive through and all 3 and lights came on and stayed on till next morning then just went away. I am at a loss on trying to figure this out. Just not making any sense to me.

Thanks again.

art_arev

Have the codes red. It could be the YAW sensor.

ACLineman

Hello,
We have a 2001 ML320 w/ 170k miles. Last night I had the same thing happen that original poster described with the exception of the brakes being applied (or at least it didn't feel like they were applied)

pulled out of driveway and started accelerating, hit approx 35 MPH and the yellow triangle with ! started flashing and could not accelerate any faster. Felt like the gas pedal hit a flat spot or there was a governor on the engine. While limping it to
our mechanic and stopped in traffic the triangle went out and the ABS/EPS lights came on. Once traffic started moving the vehicle excelled up to road speed and you could drive 50/55 mph no issues (maybe faster but that was the posted speed limit)

Mechanic put it on the scanner and it showed no engine/transmission codes but had a brake code and he suggested we try and replace the brake light switch which I've seen has been mentioned and tried in this thread (but doesn't sound like the culprit )

Was too late last night to get the part and we were going to shoot for Monday. He reset the code and the lights went out, on the way home it started again with the triangle flashing and the car not going over 35 mph. I decided to try to put it in neutral and rev the engine and that seemed normal, the engine would Rev up to 4/5000 RPMs, However when it was in gear it would not go above 1-1500 RPMs and only 35 mph (unless held to the mat, added additional info about RPM's in next post). While in neutral the car coasted fine so it didn't feel like the brakes were on at all. Not sure if this is the same issue as the original poster but it sure sounds like the same issue minus the braking

Does anyone suspect it could also be the capital YAW sensor, or is this some type of separate issue?
Thanks in advance

Maj. Dundee

And what was the brake code? It has to be a Cxxxx?

ACLineman

Um, That I didn't ask him. But I can find out

Also another thing I forgot to mention in my first post,
I tried pushing the accelerator all the way hard to the floor, the RPM's would go to 3-3,500 but the speed would NOT increase. If I let off and coasted, the vehicle would get under 35 MPH the triangle would go out and you could then accelerate back up to 35 but no higher and again the flashing triangle,,,,,,,,,,,,,,,,,

Thank You

Aar Sto

If you are having BAS/ESP problems and think it might be one of these sensors, consider if you have had a recent spill in the shifter area. The sensors are underneath on my '04 ML350. I spilled a little coffee in this area and the BAS/ESP lit up for a couple of days. Before spending hundreds on a sensor, it might be worth popping the shifter and cleaning and drying the sensors and all wiring harnesses/connections.

ACLineman

very possible. It's our sons car. So it's hard to tell with him but I'll ask