HigherOctaner

Hello All, I have a 2011 ML550 with about 100K on the clock. Recently it has abs light on, also that triagle warning, with message "BRAKE EBV, ABS, ESP inoperative, see operator's manual".
Sure I did the research, common issues include the sensor, or the magnetic ring, but recent ODB scans made it confusing:

1) 1st scans shows L6/1 and L6/4 have legit and consistent readings, while L6/2 and L6/3 showing 0
L6/2 and L6/3 dies at the same time???? highly doubt it but I moved to 2)

2) removed the right front wheel to check L6/2,
Unfortunately I did not know how to press the silver wire clip at the retainer, so was not able to remove and test the sensor resistance.

3) Several days later, with no fix to the car, one morning it suddenly displayed message "Parking Lamp Front left", visually checked it seemed legit as the lamp was not working.
Then next morning I started the car, the message went away, and the light worked without any issue ????

4) Several days later again, no fix/change to the car, the one touch window button stopped working for driver and passenger side 1st row window. No message on the dash. It also went disappeared ( returned to working fine ) the next day. ???



5) Just today, with the abs/esp light on, I tested the wheel rpm sensor scan again IN PARK GEAR, which showed that:
L6/1 L6/2 L6/3 all read 0mph but L6/4 showed 15mph ???? confused again, according to 1) L6/4 should be good????

And while driving/ in D gear, L6/1 L6/2 L6/3 all showed 0 mph BUT L6/4 showed correct mph that seemed correct based on my feeling. ???? confused again.

Based on the non-sense rpm reading in 1) and 5) , and 5) in PARK vs 5) in Drive, also the fact that abs issue interleaved with the Lamp issue in 3) and window button in 4) which both went away overnight, tt makes me feel the car is haunted.

So friends, do you have any idea what might be wrong? or what else I could check ? ( check the ohm of all 4 sensors might be one, but I have only 1 scissor jack making it labor intensive ) , Any advice would be much appreciated.

I've left question marks ??? at places that seem really confusing to me and I dont understand.


Photo for 1)

Photo for 1)

Photo for 3)

Photo for 5)

wankel8

How's your battery? Try charging it and testing.

efzauner

I have an R350 2011, and since posts on that forum is rare. I figured I would spend time here because of the similarities.

I had random warnings also, transmission locked, no abs, no srs etc etc.. I would charge the battery overnight and it would start ok but then the warnings came up again.. Turns out it was the alternator.. bad regulator, overvoltage... causing all sorts of buss and sensor warnings.

BlackML550

100%. Test your battery and alternator. Even a small drop in power can play havoc with multiple modules all over your car. Also check your terminals and that the grounds are tight and clean and making good contact. I had a similar poltergeist a few years back in a different car. The dash was like a xmas tree. In the end, a new battery fixed everything.