mercedesUSA

Got a head scratcher here. 2006 E350 has abs/esp light on, when driven over 30mph, transmission disengages (engine just revs) until I pull over then trans engages. Just got my new Star scanner setup. And all the fault codes indicate rear left speed sensor signal is implausible. I brought up the real time values screen so I could see each wheel speed signal, and took it for a drive. All 4 speed signals are same until I get over 30mph then the rear left signal stops increasing as I go faster, while the other three continue to increase in value. I figured I had a bad wheel speed sensor and replaced it. Took it for a test ride, but same symptoms and same signal pattern. Could this be a bad reluctor ring on the axle? Why does the speed signal on that one wheel stop rising after 30mph?

Anyone ever experience this?

thanks for any input

Plutoe

you did use an MB part for replacement dident you

ItalianJoe1

If the module is seeing a signal, it's unlikely the sensor is bad, but an aftermarket one could be questionable. I'd check for wheel bearing play/damage, as the ring is in the bearing I believe on that application. You could easily swap the sensor from one side to the other to rule it out, but beyond that, the next step would be a random brearing replacement, or running an overlay wiring to test the output from another one on the pins for that side, to rule out the bearing or module. Could swap the wires for LR/RR at the control module, check if the speed still shows bad on the LR, it's the module, if it goes RR, it's the bearing.

mercedesUSA

First, thank you for taking the time to help me get thinking in the right direction. Unfortunately I installed a Bosch sensor. I did not know all the aftermarket ones were to be avoided, I won’t make that mistake again.

I like your idea of swapping wires at the module Joe. I’ll give that a try tonight when I get home from work and report back what I find.

thanks again

mercedesUSA

Well i invested some time tonight with WIS trying to identify where the connection points are in the rear wheel speed sensors in hope of finding one where I could swap the wires for left rear to right rear to narrow down if it is a bad reluctor ring/ bearing or a bad ESP controller. I found the wire diagrams and location of connectors and components in WIS. after a couple of hours, and found a connector called X62 in the fuse box in the engine compartment. Same box where the ESP control unit is. I thought I could swap the pins, but before I started trying to pry on the plastic tabs that hold in each pin terminal, I figured I better look up the part number printed on the X62 connector to see if is available, because old plastic that goes through many heat/cold cycles tends to be brittle in my experience. Been there, done that. Part number printed on the connector is 220 545 69 26. Just as I suspected I can’t find this thing anywhere online or in EPC. So I’m not going to attempt to swap wires unless I know there is a way to replace it when it breaks. Tomorrow morning I’m going to attempt to rig up some jumper wires with modified crimp ends to fit the pins and sockets of each connector and see if get that idea to work.