W211 E320 CDI ESP and ABS fault
 

Suddenly, the esp and abs show faults on my car, has anyone experienced this before and what might I do to address and fix this issue? Also, the car feels like it has no power steering!

Thank you in advance

Make sure serpentine belt OK 1st.

The serpentine belt is fine! I think this happened once before and for some reason the power steering seems to go out when it does!

The steering rack has some sort of electronic input, or maybe output, that is used by the stability control system.

When some faults in the ABS/ESP systems are encountered the steering rack function is put into a default mode and the steering feels weird.

A scan tool should help you figure out what ABS/ESP issues are and the steering will go back to normal when the codes are resolved.

I had this issue and the problem was a wheel speed sensor.

The power steering takes a vehicle speed reference, and this is used to operate an actuator in the hydraulic circuit. This makes it loose when parking but tight at high speed. If it loses its speed reference it goes to tight mode all the time.

There is a steering angle sensor and this is used as an input to the ESP so the car knows what the driver is telling it to do. This is in the steering wheel hub.

I agree it’s probably a wheel speed sensor going bad, these cars need the speed signal from all 4 wheels to agree and if they don’t they will throw the flag.

Either a true Xentry or a scan tool should be able to tell you the 4 wheel speeds. Slow roll in a parking lot is enough to tell what is or is not happening.

I agree too, a wheel speed sensor. Can I use my Icar soft Mercedes scanner to reset it so that I can use the car while waiting for the new part to arrive?

No I don't think there is an override for that. If the sensor has died then you're pretty much going to have to replace it before it will reset.

Check your brake bulbs , if they are the double filament type check to see if one filament has blown and is laying across the other … had the esp /abs on my Jeep GC although mine only popped up when the lights were put on

211 not like the older ones, the rear stop lights go to the rear SAM not the cruise control module. If you lose rear lights it will just throw alarms on the speedometer telling you which bulb died.

This happened to me. First step was to replace speed sensor (that's what the scanner said). But my mechanic told me it could end up being a bad/rusted reluctor ring...which it turned out to be. So I just replaced the axle.

It is possible to replace the ring....but it's a difficult job, way above my pay grade. And probably would have been more expensive to have my mechanic go that route.

https://www.youtube.com/watch?v=Xsqy8TeEcA8

So first step is to replace the sensor. If it's still throwing codes, then it's a bad ring.

Front or back wheel? If it is the front the reluctor ring is part of the wheel bearing assembly. In the back it is part of the rear axle shaft. If your car lived in the north it is entirely possible that due to road salt it has been eaten up.

It's the front, appears easy to replace, is it just plug and play?

I've removed the faulty sensor cleaned up everything (mine was rusty) reinstalled the sensor and all was good from then on. That worked 2 times a third time I needed to replace the sensor.

The sensors can be tested by placing the end close to an AC magnetic field and measuring the ac from the wires should be about 2 mV.

So, I replaced the front wheel sensor and the faults cleared immediately, this was last Saturday. Today I drove and the faults came back...... any suggestions???

Did you clean everything all rust, grease and dirt before you tightened down the bolt holding the srnsor?