My '02 ML320 has recently started to brake on it's own while driving, an issue of the ABS system. If I start the ML and the ABS light is on, then it will NOT have the issue. If I start the ML and the ABS light is NOT on, then it's likely within the next 5 miles that I will be driving and suddenly the ABS brakes begin to brake heavily. I have to pull over and wait for the ABS light to come on. As soon as the light is on, the ML will not have this issue again.

Obviously, there is a censor or module with issues. I don't need the ABS, although I'm interested in fixing the problem. In the meantime... CAN I DISABLE THE ABS?!? Is there a fuse just for that system?

Please help. I'd like to still be able to drive this thing, the brakes work fine. I have new rotors, pads both on the front/back.

The last few times the issue has happened the ML has literally come to a screeching hault. Luckily the person behind me didn't rear end me.

Could it be a wheel speed censor?

This needs some high level diagnostics. Not a wheel speed sensor.

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90 300TE 4-M
Turbo 103, T3/T04E 50 trim
T04B cover .60 AR
Stage 3 turbine .63 AR
A2W I/C, 40 LB/HR
MS2E, 60-2 Direct Coil Control
3" Exh, AEM W/B O2
Underdrive Alt. and P/S Pulleys,
Vented Rear Discs, .034 Booster.
3.07 diffs 1st Gear Start

90 300CE 104.980
Milled & ported head, 10.3:1 compression
197° intake cam w/20° advancer
Tuned CIS ECU
4° ignition advance
PCS TCM2000, built 722.6
600W networked suction fan
Sportline sway bars
V8 rear subframe, Quaife ATB 3.06 diff

Look up "yaw sensor" I have read that this can cause your problems.

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2009 CLS550 55,000
2004 ML350 144,000
2004 X5 95,000
2002 X5 165,000
1996 320S 155,000 (sold)
1991 190E 192,000 (sold)
1989 300SE 160,00 (sold)
1984 300D 210,000 owned since 85, (sold)
1984 300SD 160,000 (sold)

Thank you!

Gathered this much so far..."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.

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. "

I guess I will start by unplugging the battery cable first.

I've seen faulty wheel speed sensors cause this problem many times. Find a shop equipped with an MB SDS. I'd bet that if you read the actual values while the vehicle is moving you'll see one of the sensors sending a plausible, but inaccurate signal....

Thank you, ILUVMILS! I've been meaning to get an MB SDS, but they are still kind of expensive for my budget. I have a mechanic with one of these and he loves it!

Mercedes Benz Professional Diagnostic Scanner Tool ABS Code Reader Icarsoft I980 | eBay

They seem to be able to do most of what I need. Do you have any experience with these?

Just a bit.......

The C1120 ESP Yaw Rate Sensor N64 or Sensor B 24/15 code shows up in every scan.

Seems logical to start by replacing the Yaw Rate Sensor, right?


Thank you all for your help

Replaced the Yaw Rate Sensor and everything has been fine! The ABS light has stayed off and there have been no recurring issues since installing the new sensor.

How is that for some high level diagnostics, duxthe1?

Thank you Dave Horvath for the recommendation!

We really appreciate everyone's assistance.