Hello MB World Forum!
I've been watching the forum pretty closely since I got my 2011 E350 Wagon 4Matic several years ago. The group has helped me quite a bit with various repairs, like brakes, thermostat, air springs, and alternator/belt repairs just to name a few. All in all, I think this group has saved me at least $10K based on prices from my local dealer. So, first and foremost, thank you!

My newest issue is a bit of a puzzle. I'm seeing the following lights and error codes, even after replacing the Left Rear Speed Sensor. These errors pointed me pretty squarely to a failed speed sensor, but apparently, I was wrong. Looking for some advice on where to go next, other than to the dealer! Before replacing the speed sensor, I checked fuses closely. My research told me that #1, 14, 20 were all related to ABS/ESC. All looked AOK. Also, the scanner is an iCarSoft MBII, recently updated to the new firmware.

Any help is HUGELY appreciated.

 

Visually inspect sensor wiring, may need replacement.

 

Thanks for the information. This is the exact repair I just finished. Replaced the Left Rear Speed Sensor prior to the photos and scanning above codes. ABS/ESC Inoperable still persists.

 

After sensor replacement did you reset the error codes is all modules you have them? In my S-class I had the left front speed sensor go bad and it lit up the cluster like a Christmas tree. After replacing the sensor I reset faults in 5-6 modules. After that all good.

 

i haven't looked up the procedure on these cars, but every car I've had before with wheel speed sensors, you need to gap them with a feeler gauge so they are just the right distance from the 'tone ring' they read.

 

Clear codes and drive. If they pop back up, keep working the sensor, you screwed something up.

 

And was it an MB sensor? Could also be a bad aftermarket sensor. QC isn't what it used to be these days.

 

Assuming speed sensor is genuine and healthy, if rear left and right one can be swapped, do the swap first.
This will confirm integrity of wiring connection being good or bad.

When later you want to further investigate voltage/power reading on the sensors, do be careful because some wheel sensor system will auto shutdown if it sensed sensor problem.
This means you seems to not get power to the sensor because it was cut off by the system/computer and not because of bad wiring.
Recycle the starter key, OFF a few seconds and system will reset. Some system only allows 1-2 seconds of sensor failure and then it cuts power off.

good luck

 

I can report that it was not a genuine part that I used… I’m starting to think it’s a possibility that the part was bad out of the bag or is somehow incompatible with the car. I’ve been buying most parts from Rock Auto, maybe it pays to go genuine with this one. I’ll order the Merc speed sensor and report back…

 

Rock Auto is a tangled mess of random stuff.

that said, when I searched rockauto for the Mercedes PN on that "Holstein" ("Cow"??) package I noted both a Bosch and Hella PN on there for just a couple $ more than the Holstein. I'd probably eyeball the original factory part and see if it has either Bosch or Hella logos along with the Mercedes tristar.


Bosch

Hella

 

Unfortunately, I just replaced the Rock Auto Sensor with a Bosch from FCP Euro, which had the Bosch markings as well as the Merc Star logo on the plug end, and no difference. I’ve cleared all related faults, test drove the car, and they all came back within minutes. Faults are identical to those in my original post. Any ideas where to look next? Any help is appreciated. Thanks.

 

Move on to pulse (reluctor) ring that sends signal to sensor. EPC shows these part #s for 2011 212.287 however, some online sites are claiming they will not fit, VIN?

 

Without a scope to verify sensor reading and the reluctance magnetic wheel magnetic signature as read by the sensor ( healthy sensor).... its kinda tough.
https://www.picoauto.com/library/aut...ensor-digital/

 

that ring is NOT easy to install, you need a press with the right size tool

 

VIN is
WDDHH8HB3BA253400

I assume the difficulty is in removing suspension arms and getting the hub off axle end. Are there any ways to press this ring on without special tools?

Many thanks.

 

here's the procedures to remove an axle shaft and install the ring on it.

 

 

Just wanted to report back that the pulse ring was indeed the issue. When I got everything apart, I saw that the magnetic layer of the pulse ring had separated completely from the metal ring. I had to peel the magnetic strip out of the inside of the hub assembly. So, as the wheel turned, the ABS sensor recorded no movement. I purchased the new ring for $30-ish from FCP Euro and spent about 5 hours in the garage completing the job. An unplanned complication was the amount of rust and condition of the park brake springs in that wheel, so I changed all that too. I now have the right side park brake on my to-do list. All in all, it wasn't a fun repair, but wasn't difficult either. I do appreciate the guidance that this forum offered me through the process. I'm guessing it just saved me another $2,500. Thank you!

 

Awesome....... good to hear ur happy ending.

Same problem as this guy, the magenetic coating went bad too. Start at minute 17:00

 

Eric O. from YouTubes' South Main Auto channel has several videos on diagnosing wheel speed sensors. In this video he put a scope down the speed sensor hole to take a look at the tone ring which seems like a good thing to try before pulling everything apart. He also uses an oscilloscope to diagnose as well.

 

I am receiving this warning in my 2011 W212 wagon. However, all functions such as ignition or interior lights are off line. I have replaced the starter battery which was old, as well as the small dashboard auxiliary battery. I have tested the fuses for ESC operation in the engine bay fuse box where they are good (numbers 1,4,14, and 20 if memory serves). The circumstances of this failure may help; I had completed a long seven hour drive home receiving one ESC error message when stopping near home. The car turned over and I made it home, after which it was bricked. I have owned this car for over a year without incident. The rear air bag suspension failed on both sides about a month prior to its failure to start. I have had this wagon towed to two different independent MB repair shops in the Raleigh NC area, neither of which offered a path forward. Any assistance is greatly appreciated. I do have a video of the dashboard display with the warning only briefly appearing as I tried to turn the ignition key, which I could post. Thanks in advance.

 

You need to do step one in the thread which is to get a scanner that can tell you exactly what is causing the ESC error. The person who originally posted had the car scanned and it pointed to the wheel speed sensor/magnetic ring. You haven't done the scan yet so it could be a few other reasons that could cause that error. Get an Autel AP2500E on Amazon in the $60 range or if you want one more advance, the Launch Creader Elite 2.0 for Benz which can do some bidirectional programming but you don't really need it as some of the things it can do like disable start/stop, change the number of blinks when signally, enable apple carplay/android auto on 2016+ models don't really apply or are just nice to have. The Autel will tell you what's causing the code and then you can proceed from that. Those other shops sound pretty bad if they can't scan for MB specific error codes which the Autel will do.

 

Will do as suggested and report back. Thanks for the reply.

 

I pulled several items from a scan using a Foxwell NT 510, without specific MB software installed:
Vehicle speed sensor B
Lost communication with Gateway A
Ambiant Air Temperature sensor High
Fuel level sensor A circuit range/performance
Fuel level sensor B performance

there were arcane letter/number combinations with each item listed. I can include them or a screen shot of the reader.
The car still fails to turn over. There were additional service warnings in the speedometer:

Front right SRS malfunction/Service required
ESC Inoperative, see service manual
Tire pressure monitor inoperative.

Thanks in advance for any help with this.